Flash,
I've used 777 extensively and find it to be both more powerful and easier to clean than black powder. Of the synthetics it is my favorite, but my overall favorite is the holy black. 777 is a good choice if real black is not available; it will not do any damage to your gun. Just remember to reduce your loads by 10 to 15 percent below the black powder load.
I also use lubed felt overpowder wads instead of grease in the chamber mouth and have been satisfied with them. They are a lot easier to use than grease.
Most ROA shooters use 25-35 gr fffg by volume real black powder with a .457 ball and No. 11 CCI caps. If you use Remington caps I understand that No. 10's will fit; CCI No. 10's do not fit an ROA with factory nipples. The gun is very rugged and will easily shoot full chambers (about 40 gr fffg, I believe) all day long, but accuracy will likely suffer with that max load.
Loading stand: there are two types that I've found acceptable, a cylinder loading stand, available from
www.powderinc.com for about $55:
and a revolver loading stand for about $12 from several places, including The Possible Shop
http://possibleshop.com/cap-ball-supplies.htm and Dixie Gun Works
http://www.dixiegunworks.com/product_info.php?products_id=7768:
The cylinder loading stand is overkill for an ROA; the revolver stand is sufficient, and isn't really necessary, although it does make loading a bit easier. The cylinder stand is only necessary for one gun, in my experience, the Uberti 1872 Colt SAA with the percussion cylinder, since it cannot be loaded with the cylinder in the frame.
The ROA is the finest percussion revolver made today, perhaps even the best that's ever been made. You have a fine weapon that should give you many years of excellent performance. Enjoy.