Oldfalguy -
You would have better luck getting answers if you started a new thread with your questions, instead of tacking them on to some other guy's thread. It's a bit impolite to 'hijack' somebody else's thread, and you'll only get a limited number of people reading your post.
Cap sizes are difficult to specify. First, there's no standard for sizes; CCI No. 10's are not the same size as Remington No. 10's, for instance, and they can vary even within a given brand and size. My ROA uses Remington No. 10's best, but even the Remington No. 11 and RWS 1075's will work. Others have had different results, finding the CCI's work better. The only thing you can do is buy some and try them.
Caps are difficult to buy via mail order as most places will charge you a $20 hazardous materials shipping fee on your order.
Recoil with any black powder load will be very different than with smokeless powders. It's more of a push than a recoil; you don't need to reduce your loads for the sake of reduced recoil.
The projectile MUST be seated on the powder. It is quite dangerous to leave an air gap between powder and ball.
Some folks claim there is an increase in accuracy when using filler for the purpose of seating the ball near the chamber mouth. However, that advantage is not large; many of us can't shoot well enough to notice it. I suggest you can do very well without worrying about seating the ball near the chamber mouth when just starting out; once you've gotten some experience you might try out the filler and see if you can detect any advantage.
The ROA can seat the ball on a 20 gr charge of powder. The ball will be deep in the chamber, but as mentioned above, don't be concerned about that.
Looks like it's from the '80s.