The inches doesn't matter, but the pitch does. Wait. That might end up as a sig line somewhere Ok now that that is out of my system, of you are using 3/8 .050 chain, you'll use a 7/32 size one. Yes, these are awesome gifts.
Waiting on someome to say "that's not what she said".... Yeah i know the length/drive link count doesnt matter. Except its more to sharpen, and dull haha
Definitely a grease hole. Gotta lube it up,but just the tip and only for a minute. I lube mine for sure with marine grease to keep any moisture out. My shed is a pole barn, so I try to protect anything metal I can. Also it keeps the tip happy.
The rails on the 2 in 1 ride on the cutters on either side of the one getting sharpened. The cutters are too far apart on a skip chain to allow the 2 in 1 to work.