Rooster,
I suppose whether you see any C&B action depends on who you are shooting with and when.
In the several clubs I shoot with, most of thsoe who shoot the Frontiersman category also tend to shoot other categories as the mood strikes, generally in one of the Frontier Cartridge categories.
I personally don't like shooting Frontiersman except in the Fall and Spring when its a bit cooler and the humidity is down. I find that dripping sweat into the cylinders along with the powder doesn't help the ignition much. In the cooler months that isn't a problem. Sometimes its so humid the powder turns to sludge almost as you pour it out. Not fun nor conducive toward a clean match.
I have a pard that uses multiple pre-loaded cylinders but I prefer to use three or four pistols. I load them up at the reloading table after I've shot, which allows me to help out on the posse chores while doing my reloads - which as was observed, tends to take a bit more time than just pushing in some new cartridges. If for any reason I get hung up, I've got at least one pistol ready to go so only have to reload one quickly. However, our posses tend to run large, about 20 people, so finding sufficient time to reload usually isn't a problem.
The biggest problem I've seen is that a few shooters don't seem to like C&B shooters. Don't know why, and fortunately those shooters tend to be in the great minority.
You might want to consider starting off shooting one C&B with one cartridge pistol initially to get the feel of reloading at the match, then the next time use two C&B pistols.
Personally, I'd like to see more Frontiersmen at the matches. I actually like shooting them more than the cartridge guns.