i8.0 Unique and 255 LSWC have been the "standard" .45 Colt load for over a century.
What's going on in the Skunk Works: Medium burning powders are a favorite for 45 Colt since the invention of dirt. Unique may be the most popular. My favorite is Accurate #5 with 255 grain bullets. Unique is the standard. Loads using 2400 are usually used in the most heavy loads
When powder data is not given for a caliber there
may be no satisfactory test results.
I'll be working up loads for 300gr. gascheck bullets for my Ruger's any time now. This will be a new bullet weight for me. "...any time now," means when I get bullets cast.
Alliant, maker of Unique, offers a free 2020 Reloader's Guide available on their website. Richard Lee's reloading book useful. I don't care about making my 45 Colt caliber revolvers into magnum's. I go along with what's already been suggested. Get some data and start loading 45 Colt with medium burning powder. Bullseye would be my absolute last choice for 45 Colt.