Bullseye is a poor powder for a hunting load. It is awfully fast burning for a long barrel, and pressures will peak early anyway, limiting top velocity. Reliable, tested data for it is almost non-existent in anything approaching a heavy load. From the Hornady No 2 Manual, the max load for a .45 Colt is:
250-grain HP - 8.4 grains Bullseye - 900 fps in a 4.75" revolver
This was revised in the No 3 manual to:
250-grain HP - 7.2 grains Bullseye - 900 fps in the same revolver
The .45LC case is really too large for the tiny Bullseye charges. If you do not want the Ruger-only loads, do yourself a favor and get a more appropriate powder like Unique or BlueDot or PowerPistol.