Scootertrog:
1.- The buttons should flush out the pin housing just to get in touch with the cylinder,they have to be "hand sanded" until the pin can be pushed by hand into the cylinder without any problems, they have to be "rounded" a little bit to get the same radius as your piston/cylinder wall. I will post some other pics tomorrow so you can see them on the piston.
2.- No problem to remove them, they are the same diameter as your piston pin so they flush free inside the pin's hole, they do not melt, Teflon is a high temperature resistant material, you could melt your aluminium piston first.
3.- No way to add a considerable mass, teflon is very light, I will check the weight tomorrow in a precision scale and let you know.