The 1851 design is a good one for a beginner. It's very forgiving. Should you forget to load powder and ram a ball down, you can remove the barrel assembly and the cylinder.
Remove the nipple from the offending chamber and trickle in some powder. Replace the nipple and cap it.
Then, with the barrel assembly still removed, fire the ball out of the cylinder. You'll just get a POP! With the Remington, you must fire through the barrel, which with very small loads can cause the ball to stick in the bore and then it's on to solving another problem!
The 1851 Navy is exceptionally well-balanced. Even the trick and exhibition shooters of today will tell you that as far as balance goes, it can't be beat. The later Colt Single Action Army is most-often used because of the convenience of cartridges, but if all you need to fire are six shots or less, the Navy will make a dandy gun to shoot blanks.
Be very careful with blanks, though. The wadding you ram down on top of the powder can injure someone at close range. The flame can too.
The 1861 Navy was an improvement over the 1851. It's streamlined and has more room between the rammer and cylinder to accommodate conical bullets, should you wish to use them.
For best accuracy, the Colt system demands that the wedge is in tight. Use a nylon or rubber-faced hammer to tap it in, while rotating the cylinder. When the cylinder begins to drag, stop! Then turn it over and tap the wedge OUT very lightly until the cylinder moves freely again.
This is the Colt's "sweet spot."
I like to soak my felt wads, either store-bought or punched from old Cowboy hats with a 3/8-inch punch, in a lubricant mix of paraffin, beeswax and mutton tallow.
Search this site under my name, "Gatofeo" for detailed instructions on making this lubricant and preparing the wads.
In my Colt 2nd generation 1851 Navy I regularly shoot 22 to 24 grains of Goex FFFG. This is a full load but I get my best accuracy from it. Sacrificing the felt wad, I can get up to 27 grains of FFFG in its chambers, leaving just enough room to seat a lead ball. Then I put Crisco or CVA Grease Patch over the ball. That 27 grains is a whoop-and-holler load!
I don't use 27 grains much, though. No point, if all I'm going to do is plug paper targets and tin cans.
As for caps, you will have to determine that yourself. Nipple sizes vary among makers, and even change with the maker as time goes by.
I suggest you buy a tin each of No. 10 and No. 11, then see which fits best. I always pinch my caps together into an elliptical shape, to cling to the nipple. Keeps them from falling off during handling, or blowing off from recoil.
The caps that don't quite fit may be used to clear the chamber, before you load it the first time. After firing a cylinderful of regular loads with ball, it's rarely necessary to fire caps on it again to keep the nipple vent clear. Blowback through the vent and against the cap usually keeps the vent clean.
The Colt design shoots high. Always has, even the originals. Some shoot just a little high at 25 yards and some shoot a LOT. To compensate, you can add a taller front sight and, if necessary, make the notch in the hammer nose a little deeper. But go slow on t his, and don't do it until you've found an accurate load.
So, you're in for some experimentation with loads, powder, caps, ball size, lubricants and lubrcation methods and so on to find that accurate load.
I suggest you start with 20 grains, a greased felt wad, a bit of corn meal on top of that wad to take up space and a .380-inch ball. I've had good accuacy luck with this combo in my other .36s (In my 1862 Pocket Police repro this is a maximum load and I don't need the corn meal).
In my .36 Remington it's a very mild load; the Remington can take up to 30 grains of FFFG. It's a rip-snorter!
Welcome to cap and ball revolver shooting! You're hooked! And may God have mercy on your crazed soul! It's a sickness ... we should all be wearing little, powder-gray ribbons in remembrance