Not a mechanic but I do all my own work.
I would slap a level on the table and move it around. Find the low spot and make an adjustment of the feet and keep doing that until it is better. Can’t hurt, you can always reverse it and it won’t affect the slate.
Now if the slate is uneven then you will still see the issue and that will require disassembly.
I'm in the same scenario. The table guys around here are hacks with a capital H. I got a used Starrett machinist level on eBay for $165 shipped. It's paid for itself many times over and I can always resell it if I ever wanted to.
Leveling tables isn't rocket science, but there is an art to it. It pays to be meticulous. I think the first time I leveled and seamed my old Olhausen it took me a week or so to nitpick it and get it perfect. But it was done right and I didn't have any weird roll offs. It's the type you use wood shims. Tables with built in levelers are a bit different but easier in the long run.
It's something that almost anyone with patience and who can nit pick can do. Realkingcobra has a 3 piece slate leveling document here on the forums and his YouTube channel has a ton of invaluable info. The part where he shows how to level seams with a bottle jack is genius.
When I bought my Diamond, I watched the installers do a hack job on the seams but figured they knew what they were doing. Spoiler alert: They didn't. They seamed the 3 piece so badly balls would roll off 4" when going over the seams. They didn't flush them up. When I scraped the wax off one side was tissue thin and the other was about 1/16-1/8" thick. I used turpentine to remove all wax residue, re did the seams with super glue and a tiny amount of bondo. I used the jack trick to get them perfectly flush. I had an idea of how to level with the levelers but Glen was gracious enough to walk me through the process on the phone for about an hour or so.
But anyway, sorry for the book, but I'm with you, doing my own work so I know it's done right.
