The .32 ACP pistols I have measured have .308-.309 bores. I don't load .32 ACP much these days, but Hornady used to sell a .309 conical lead bullet (I don't remember the weight, maybe 90 grains) which worked well. I suppose you could use a larger diameter bullet so long as it didn't bulge the case enough to cause difficult chambering. Regarding loads, I don't remember what recipe I used. I also remember that I once loaded some 93 grain FMJ bullets intended for the .30 Luger (or maybe .30 Mauser) which worked OK. Also some 100 grain Plinker half-jacketed bullets. Experimenting is fun.