Imagine this; I've mentioned in the review of my Pietta Starr SA that the design is sort of a one-off curiosity, and that the coolest thing about the design is that it's a break-top like the S&W Schofield. Yes, that is mondo-cool, alrighty...but also as I mentioned in my review of it, it really doesn't buy you anything. The thumb screw is a fine-threaded screw and takes a number of turns to loosen it. Once you do, it comes free of the gun. Bottom line, if you dropped it in the heat of battle, might as well chuck the gun. It's useless. From what I can see, it's design purpose was to allow quick disassembly and easy access for cleaning. Even if spare cylinders were available, you can swap cylinders on a non-fouled Remmy faster.
But, just suppose...Ebenezer Starr had the foresight and ability to replace the thumbscrew with a captive, spring loaded camloc-style 1/4 turn fastener with a folding wingnut grip?
And sell this gun with two extra cylinders? The wingnut, folded, would impose no interference (and if it broke off, there could be a screw slot on the end of the stud for removal), and would allow the action to break and flip down in mere seconds. A new loaded cylinder could be inserted in three shakes of a lamb's tail and...game changer. 18 shots at the ready. Naturally there would be some risk in carrying loaded and capped cylinders (would have to be protected against accidental discharge in some manner) but think about the implications!