Check out the reloading data side of the Winchester web site... You can safely use the charge range listed without issue. I actually made up some loads to test out the .45 (1911) IPSC race gun that was my father's. 185gr projectiles loaded from the middle of the range to the highest charge level performed flawlessly. Of course, with the comp on the gun, it stayed pretty level at the top end of the range.
I would go with Win 231 first, if you can score some. If you're willing to travel, Acme has some Bullseye in stock (as of yesterday afternoon at least). Price is in line with what you would expect too (reasonable). Just be sure to use standard primers with the powder first. If you go with magnum primers you need to adjust your powder charge accordingly.
BTW, I was using 4.6gr of Win 231 with 255gr flat tip projectiles in my .45 ACP IPSC (limited class) gun. Shot really nice, and with the right recoil spring (a variable) the gun handled it really well.