Power Pistol is good for a bright flash, but you can't use a whole lot of it in .45 ACP. For a night-time photo shoot, I loaded something like 14 grains under a 135gr bullet in 10mm, and it didn't disappoint.
Once you find your powder, I'm thinking that you use 155 or 165 or 185 grain bullets so you can use a greater quantity of powder. Heavier bullets (like 230g ball) use less powder. That isn't what you want.
If you still want round nose bullets, get Berry's 185 grain RNHB (round nose hollow base). Load them to the same 1.250" and they look just like GI issue ball ammo. No one will know the difference.