I'm with you on enlarging the hole in your strap, but for the screw-bass part, the easiest and best way I've found is using the original bass screw and the Schaller StrapLock together.
Drill the StrapLock button out very slightly to take your original screw then simply screw back in. No adjustment or mods needed to the bass at all and the connection will be as tough as nails, after all it's using the original screw.