Richard,
My gear leg sockets were in the same condition as yours. I had powder coating inside the socket and tight spots from the welding, which appears to have been done AFTER the sockets were sized.
I purchased an import adjustable reamer from MSC. I sized the reamer .001" larger than the gear legs and reamed the sockets to size. I don't believe you can keep a tight fit the whole length of the socket, cleaning up the socket by hand.
I mounted the reamer in the chuck of a friend's engine lathe. I used the tail stock to center the opposite end of the socket with the chucked up reamer. Using only my hand, I rotated the chuck and fed the socket into the reamer. This method was quick and easy. It produced excellent results on my 8A sockets. Two local RV-9A builders had the same problem, so I performed this clean up on their sockets as well.
Charlie Kuss