Pure opinion on my part- there ARE Bullseye loads in the manual for 45 Colt- but that is a REAL big cartridge case. B'eye seems to do best with lighter, cast bullets- around 200 gr. As you move up in size, I would go to Unique or 2400. There are probably better powders around- I simply always have Bullseye, Unique, and 2400 on the bench. YMMV.
C3 is right, bullseye wouldn't be the first choice for 45 colt. I've been loading that caliber for 25 years and done a lot of experimenting. The most accurate load I've ever had and one I use almost exclusively in the Ruger is 9.5 grains of SR 7625 with a 255 grain cast swc. However that is listed in the Lyman manual for strong guns like Ruger and TC Contender. Chono'd at 950 fps with a 5.5 inch Blackhawk. If you want more powerful loads go with the slower burning 2400. I find that if you push the 45 colt past 1000 fps the brass doesn't last too long.
What are you looking to do with this load? If I were to guess, you're looking at mild to midrange loads (Bullseye's forte.) As previously noted, Bullseye probably isn't ideal for that application. I'd look for bulkier powders that don't mind lower pressures. Unique will work, but is a bit dirty at lower pressures. It gets much better as pressures climb though. I haven't used it myself, but you might want to check out Trail Boss. http://www.gunblast.com/IMR_TrailBoss.htm
