Bullseye is real fast burning powder, useful for light shot loads in 12 gauge shells. I would use Bullseye in 7/8 or 3/4 ounce 12 gauge loads at target velocities. Keep looking, you will find a load. Send them an email, they will send you a load.
I understand your concerns. However my Hercules manual shows 3gr of RedDot and 3gr of Bullseye with the same ballistic info for 38 special. My suggestion was to check the manuals. I don't understand why you would tell someone to ignore that suggestion.