Some other thoughts that came to mind…
As silenus says, cleaning is very important. Black powder attracts water. If you leave the residue in your revolver, it will rust.
Cleaning is simple, but can be very messy. I clean mine the old-fashioned way: with hot water. I use rubber dishwashing gloves, because the water is so hot it will burn if I don’t. Using hot water heats up the metal so that any water left after you dry the piece can evaporate easier.
First, disassemble the revolver. Remove the nipples, and be careful not to lose them. I’d suggest cleaning the nipples first and then putting them together in a dish or something. Scrub them with a toothbrush to get all of the residue off. Use a nipple pick to clean the inside.
Rinse and brush the barrel and chambers until the water runs clean. Make sure you get rid of all of the residue!
Clean the frame with a toothbrush. It’s best to remove the stocks so that you can dry the mainspring, but be careful not to damage the screws.
Once everything is clean and dry (be sure to shake out the receiver), apply a thin coat of gun oil to everything, inside and out.
As I said, washing up is messy. You will not believe all of the black stuff that comes out!
I haven’t gotten round to getting a Remington yet. The Remington has a “top strap” over the cylinder that makes it much stronger than the Colts. But that doesn’t mean Colts are “weak”! (More on that in a minute.) You’ll have no worries with a good-quality Colt replica.
As for the spare cylinders, Clint Eastwood carried 'em! I don’t, because to remove the cylinder on a Colt you have to remove the barrel. Not so with a Remington, AFAIK.
But back to strength. The original Colt Walkers (the top one) did blow up occasionally. I don’t recall how much powder they were putting in them. The Loading Data Chart I linked earlier says they carry a max. of 55 grains. I think this might be less than in the olden days. In any case, one can presume that Colt would not put that amount there unless it is safe to load 55 gr. They wouldn’t want a lawsuit. Also, metallurgy has advanced considerably in the last 160 years. You probably won’t have any problems with a good-quality Walker replica.
What’s a “good-quality replica”? I swear by Uberti. Some people say they’re overrated. I’ve found that Ubertis I’ve seen in gun shops have a better finish than most. The Colt 2nd- and 3rd Generation BP revolvers were made in Italy. I’ve heard they were made by Uberti, but I’ve also heard they were made by another Italian company. I’ll leave it to others more familiar with them to comment on other brands such as Navy Arms, Cimarron, or San Marco.