Right now the answer might be "whatever you can find". Personal long-time favorite recipe is a plated or coated 230g ball with WST & Federal large pistol primer. WST is medium fast & reasonably clean. No reason to shoot lead. N320 is a another great powder, but expensive.
It isn't exactly what you are looking at, but I have the R1 double stack. It is a good 1911. The fit, finish, accuracy, & reliability are have all been more than acceptable.
I have exactly the same problem with a PM9. I just put the PM9 aside for the time being and use other 1911s that are not fussy about which mag from a collection of Dawson, Tripp, & Wilson ETM I stuff in them. The magwell is the same one used on the DW Specialist, but I don't think the magwell...
I've been shooting for fun and competition (really the same thing) for years and have tried a variety of pistols but I keep coming back to the 1911. Its just an elegant and effective design. Of course, that is preaching to the choir here!