I was in the same boat as you. I had recovered a couple of tables (my own, and friends), leveled them but never did anything involved like rails.
With extensive searching, and plenty of reading, and some thinking and figuring of my own - I found enough information from this forum to do it on my own. I also had to determine who's methods I liked better, who was full of crap and all that. Not all info is good info. There's bad advice everywhere. Guys like RKC, SD and a few others - treat what they say like Gospel. About 99% of the useful info I found came from their posts. I knew the moment I saw pictures of their work that these guys are serious and know what they're talking about. Hacks don't do work like that, period. This was early on before I spent a lot of time reading. Excellence shows.
Some thoughts on all that:
1. In some ways it was easier than I thought, in others harder.
2. I spent a LOT of time pre-planning and did not rush not a single step. I knew exactly what I needed to do, and how, before doing it. No trial and error, because there is no trial and error in cushion work - you either get it right or you don't. Leaving only one factor to the test, and that's my skill with my hands, which isn't as good as a true craftsman, but better than the average Joe. I did not want to have to redo anything. Nor waste any materials.
3. My cushions came out just as good as any of the top guys here who post photos of their professional work. Why? Because I analyzed ALL those photos and carefully observed them in close detail. Those photos became my standard, and I settled for nothing less. I learned from these guys. I mimicked their quality and results. I am also fanatical about detail (picky), and wanted them perfect for best play and good looks. Prior to beginning this, I had similar ideas in my head. I used to think that pockets should be like this, even though I never saw pockets that good before in person unless I was playing on a factory Diamond. It's sort of an ideal. There's the right way, and then there's everything else.
Nose height is uniform, straight and correct down the whole cushion. Adhesive bond is perfect (strong). Angles are perfect. Facings are perfect. Everything smooth. Nothing rough. Everything flush. Everything straight (no curves, concave pocket facing angles). Perfect. I used the techniques described here. For example, the belt sander method to flush the cushion before putting the facings on etcetera.
I busted out the protractor, all angles the same.
HOWEVER....to do that, took me many times more time than these pros do. They can do that, and do it fast. I did this as a hobby/project and it was fun. I couldn't do this for a living. I have BIG respect for these guys who crank out that kind of quality all the time.
4. Despite finding 99% of the info I needed, I still needed to ask a few questions here. Most of them were reassurance questions, to make sure what I figured was right, or to make sure the info was up to date since some things change a little over the years. But these are specific questions, not big general questions like yours. I don't mean that in an offensive way, but it's like asking "how do you build a boat" ...it's just too much to explain step by step. That's why it takes a lot of reading and research. It's all there on this site, just have to dig for it, and that in itself is a lot of time and effort that must be weighed against just having a pro do it. For me, it wasn't a big deal. I spent many, many hours of searching and reading - but I learned a lot of new things. If I didn't care about learning them, then I would have just paid someone to do this and save me the pain. That said, if you don't want a project and what you're really after is just getting the table redone - hire a pro. If you don't mind a project, then you won't mind the research.
5. I won't go into the fine details because it would require me typing out pages and pages, but here are the basic stages:
A. Figure out exactly what kind of cushion you need, that is profile, K-66, K-55...You have the same table I do, so that would be K-55. Buy the cushions, buy the facings you want in terms of material and specific thickness - that's a personal choice ***, buy the contact cement (Scotch Grip 10 Neoprene Neutral). And whatever tools you need for this project.
B. Take off the rail cloth, pull out the feather strip (try to do this slowly and gentle as these can be reused). If you pull hard, you'll break it. Then you have to buy another set and cut them. Not expensive but you can avoid it.
C. Pull off the old cushions and facings. Often, facing have staples or nails holding them down in addition to being glued down. Sometimes they come off easy, sometimes not. Sometimes some wood comes off with them. That sucks. This happened to me on one rail. Depending where the wood comes off, you may or may not have to repair the subrail. If you do, break out the Bondo. If the subrail is in badshape for other reasons, (old, abused) ...then get a pro like RKC to redo it completely.
D. Clean off the subrail. I did this by using stripper to remove the old contact cement. Then elbow grease with a scotch brite pad. Some people sand them with a belt sander. I wouldn't and couldn't because there was a lot of crud on my subrail and I would have mangled the subrail if I sanded it in that way.
E. Glue on the new cushions - this can be a pain. With contact cement, if you do it right, you get 1 shot at it. That is, if you want a solid bond. There are tricks to doing this, it all has to do with how you set yourself up on your work bench so you are comfortable and not fumbling around.
F. Trim off the edges which are the pockets to the correct angle, which should match the angle of the pocket subrail.
G. Sand down those edges nice and flush with the subrail. Maintain the correct pocket angles.
H. Glue facings on.
I. Trim facings down, then sand them to be perfectly flush with the rest of the cushion. It should look like a natural continuation of the cushion. So when the cloth is on, it doesn't look like there's a facing there at all. That's what I think is best. If you can see any lines, lack of uniformity, indents, bulges etcetera, it's not right. I consider that shoddy work.
Those are the basic stages.
***for facings, consider this: The pockets on a GC3 are 5" (corners). That's with the standard 1/8" facings most have. That means, without facings, the opening is 5.25" ...
Going by that, you can decide the pocket size you want, within reason of course.
For many good reasons, the recommended minimum facing thickness is 3/16" ..times two, that means the final pocket size will be 4-7/8" a touch smaller than before. Which is good. Still big, but any little bit you decrease sewer pockets is a good thing. If you use 1/4" facings, the pocket will be 4.75"...however, for the best play, it's not recommended to go beyond that in facing thickness. And to not stack facings. "double shimmed" and "triple shimmed" pockets usually play like crap. That is why the pros here, and many others recommend a subrail extension if you want to get the pocket down to the 4.625" or less range.
All of this assumes that the rail angle was properly cut at the factory. If one of the angles is cut too wide, then that pocket will always be larger than the others. There are a number of fixes for that....some good, others kind of patch work.
But I'm drifting from the main topic.
Hope this helps.