re: wearing down master link
Sorry. It just happens.
Happens with the OEM guide. Happens with the FRP guide. Don't know about a ...say Moose or other guide. Prolly.
Replace the clip once in awhile.
Probwum sawved!!
re: replacing the slipper
If there are grooves worn in it deep enough to either cause mistracking or rubbing on the side plates, replace it. I doubt that's a problem.
I run a 12T CS sprocket (makes slipper wear more), put on my first o-ring chain only AFTER the oem wore out..still used the same slipper! I have another in my 'box-o-parts', but haven't needed it.
HAVE replaced my link clip a couple of times...........