I can understand why you'd be confused at some of this info, people talking about using different rail cloth than bed cloth etc. Remember that this is often from people who compete at the highest level, and for different reasons than pure speed. I'll try to explain the technical details of it:
Wool cloth, of all kinds, tend to slide when it's brand new. If you watch a new cloth under a high power loupe, you'll see it's different than worn cloth. It's flatter, but it's the cloths structure that has been pressed flat and sometimes filled in with loose fuzz, though this is more true of nappy cloth. This is what causes the early sliding. Once the loose "fuzz" gets shorn off by wear and the proper structure raises up correctly, the extreme slide goes away. The more "fuzzy" or "nappy" the cloth, the longer it takes for the cloth to reach it's actual speed level. So a very thick, fuzzy nap cloth will still play slower than Simonis 760, but the speed will take longer to approach it's intended level. This is true, also of the cushions. Slidy rails will affect the rebound angle of bank shots (make the ball go "long") and make the pockets play easier.
Thicker cloths will take some time to break in on the rails. Simonis 760 is thinner and has less of this "rail slide" which is why, at one time, it was suggested to use it for the rails instead of 860, which was used for the bed. What I call rail slide is more a combination of the thickness acting as an extra cushion and the slidyness of the cloth itself. Simonis 760 is slidier, but thinner, but the net effect is less rail slide IN THE VERY BEGINNING OF THE CLOTHS LIFE. Keep in mind that this is for tournaments where everyone has to play on brand new cloths. For a home table all of this can be safely forgotten about and as far as I know, nobody has even talked about this since the 90's and early 2000s. It's a more common topic of conversation in snooker. Recently redone rails (with the nap and extra thickness of snooker cloth, and it being pure wool) tend to bounce less and bank long. AGAIN, for a home table, it can be safely forgotten about because the problem exist for a minute fraction of a cloths life, and the table will be perfectly playable, just play slightly differently for a short while. I would love to see if an amateur can even notice the difference between different pool cloths on the cushions? It's more for monsters like Earl to worry about, I'd say.
Theoretically, a thinner cloth will also cushion the ball less before it reaches actual rubber. I doubt that will be significant for speed test like the one suggested. It's more for the very soft hits, and only in the very beginning of the cloths life. After a week or two, you can forget about this whole thing, IMO.