The cylinder in my Palmetto Whitney looks almost identical to the Spiller & Burr cylinder on the left, rather than the real Whitney as on the right. Whether or not they'd interchange ... dunno. There's an obvious difference in how the ratchet slots are machined that the pawl moves but I don't know what that means.
The safety slots on the Palmetto also more closely resemble the Spiller & Burrs slots rather than the ones on your original. Thanks to the way Palmetto machined the hammer (incorrect profile) they are totally useless on the Palmetto; the heel of the hammer hits the base of the cylinder. A Dremel might correct that should I somehow come to believe that using the safety slots was important. Palmetto .... *!SIGH!*
I know I have a Pietta Spiller & Burr and the two cylinders will not interchange. Nor will the arbors change.
The Root revolver is a very interesting one.
As I said, the barrel on mine wasn't indexed correctly. On Roots the cylinder index (or locks) on the rear end of the arbor. There are no slots milled into the cylinder. The arbor rotates and the locking lock pops up from below at the rear of the gun.
This works because the arbor has a square piece machined on the front that fits into a mating part on the cylinder. Because of this weird set-up, when reassembling the gun from cleaning, if you don't "guess right" when seating the cylinder, the revolver will index exactly in between the chambers, necessitating a do over ... and a better guess.
Because of the high price these go for I am going to say I ultimatly do not think they're really worth it.
The gun indexes OK (when I guess right about re assembly) but it's a little loose sideways. The wood grips are crudely finished, though perfectly serviceable.
I'm sure if Uberti made this they might charge more but make a better product in the end. If the Palmetto was cheaper then I'd say OK ... it's rather like the old Armi San Marco guns. They did work but weren't always as "pretty" as they could be -- especially in the company's later years.
If you're in a position where you can't afford big expenditures and want good results then I would advise you to pass on the Root.