never used a pc for lsp removal but i would probably use a non abrassive one. as far as color that depends on what pads you have. some gray are heavy cut (like malco's) some are non abrassive.
I almost always remove Zaino polish by hand but have used a wool pad and a MF bonnet over it in the past. The main problem with using a bonnet covered pad is the build up in the bonnet happens rather quickly. I have several MF bonnets and have to change them out very frequently.