just to chime in… (advice is worth what you paid) - dont grease the cables. I’ve seen where that leads, and it’s not good.
+1 - pull the felt out from the slider end. I used a dental pick, you use whatever makes you happy.
The slider needs to have about .0125” of material taken off of the top & the same on the bottom in order to fit in the channel nicely. (if you want to do it evenly)