Gosh, some huge misconceptions...,
Some facts folks..., black powder weapons were used for centuries for SD. The caplock replaced the flint because it wasn't as reliable as caps. The revolver replaced the single/double barreled pistol, as 5-6 shots were better than 1-2, AND..., cartridge ammunition was developed because..., caplocks weren't as reliable. All of that being true, a caplock revolver is a viable SD tool in some cases, and I know first hand of several men and women living in Washington DC who owned them and used them on their own property for SD prior to the change in the DC gunlaws. Actually they still use them..., as DC really hasn't made it possible yet to own a modern handgun.
(Since the thread isn't about what I would chose, I won't offer my opinion on the merits of the cap-n-ball vs. a cartridge handgun.)
Other facts to consider..., police training levels are not a good standard to gauge your own need for, or level of, training. Most LEO are very undertrained in the use of firearms.
It's fine that one has combat experience, be it Europe, the South Pacific, SE Asia, Central America, or the Middle East. Consider that the weapons used bu US forces were semi-automatics, and folks that went to those conflicts were trained prior to being sent into the field, regardless if they wre novices or had been hunting and shooting since they could walk. Being proficient with a 1911A1 or a newer style pistol may be the same as with a Colt 1861 Army when it comes to accuracy when the trigger is pulled..., it isn't the same when talking about function and clearing jams.
So you should practice, not just for marksmanship, but to understand the weaknesses of the revolver you have chosen. I have seen novice single action revolver shooters short-cock their revolvers under stress when at a CAS match..., stress is a bit higher, wouldn't you say, when facing an actual intruder? Another example, 20 grains of BP might just "blow" your caps, and blown caps can dislodge and fall into the mechanism, jamming the revolver. 20 grains might not blow your caps, and no worries..., but you don't know until you try it. (I know this from personal experience) Reducing the load by just a few grains can stop blown caps in some cases, while leaving you with a still viable SD load. If the problem continues, and you continue reducing the load, you may find that you need after market nipples on your revolver to keep a proper SD powder load while not blowing caps and risking a jam. Again, how do you know until you test this?
Also,... Do you need two Colt style revolvers, or do you need one Remington, and one spare cylinder to reload, or are you figuring 6 shots is enough? One famous lawman and shooter of note, Mr. Hickok, carried two Colt Navy revolvers for some reason. It's your choice. If you go for a Remington and a second cylinder, shouldn't you practice swapping out the cylinders?
In closing, I for one sincerely want you to stay secure, and would much prefer to one day read that you are safe and sound and survived a deadly encounter than to read that your revolver jammed, or misfired, or fired a squib load and your next shot blew up the revolver as the first bullet didn't clear the barrel. I'd think the best way for that good scenario to happen is for you to practice with your chosen handgun.
LD