covered at: Recover your ugly saddle, Patching Small Hole in Leather Saddle in bike.tech archives plus one i cannot find
the goop saving idea is a good one. i mention this again after the saddle, a spec minkow lost a three rounder to a pond pine falling down the trunk in HD touring trim leaving the seat rough sans covering one the abraded side.
I bought a new tube and forswore butt grease for several weeks but after a good virgin tolulene spread the temp fell from 70 to 50 in 3 hours so i used the antique seat, soldiered on and left the gooped spec in the shop for a week-several days beyond the recommended cure.
the extra cure time results, with a new tube,in a very acceptable "new" skin and is highly recommended.