147,
As an old IPSC shooter, I don't think much is to be gained in the + P ammo. After all 230 gr. has been doing it successfully since 1911. They use an 18 lb. spring for that load. I might go up to 20 lbs.
In my Commander I use a 22 lb spring, but I don't think that I am gaining very much. My load duplicates hard ball: 230 gr. rnd nose bullet behing 6.5 gr of Unique.
Just duplicate hard ball loads and you will be all set. Your pistol will last forever.
Jeff Cooper's optimum load for the 45 ACP was the 215 gr markell (?) bullet behind 7.5 gr of Unique for about 1,00 fps.