I like your 25 ACP Super Single Six 8 shot! As you can see below I lean towards the short barrels.
My first foray into multiple cartridges was this Single Six in 32 H&R mag.
New Model Single Six Magnum .32 H&R Mag/.327 Fed Mag and extra .32-20 'Short' convertible cyl, loading chute enlarged slightly for larger .32/20 case rims.
Bisley hammer with modified spur, Stainless Steel grip frame, steel ejector rod housing, SBH grooved trigger w/web removed, Colt ejector rod, and free-spin cylinder pawl for ease of aligning the chambers with the loading gate.
Next was: .22 Hondo Super Mag or .22-20 Winch. or .218 BEE Short
Haven't decided what to call it yet. I converted a .32 single six to .218 Bee Short.
Started by buying a used .32 single six, $400. Single six parts kit with a 22 LR cyl and 22 barrel from Gunbroker, $75. 218 Bee reamer from Brownells, $110. Total of $585 invested.
The 218 BEE and 25/20 will easily fit six in a single six cyl. The 25-20 case is the parent case for the 218 BEE (the shoulder was just extended). So that I wouldn't have to relocate the shoulder back on the 218 BEE cases, I started with 25-20 cases. Resize the neck first to .22 with standard .218 Bee dies with resizer and seating dies shortened at the mouth. Then shorten .040" less than a factory 25-20 case.
Best results is to start with a 22 LR chambered cyl. Since the chambers are charge holes (no shoulder) the chambers make better pilot holes for the reamer to follow than a 22 mag cyl. and the throats are correct size. Reamed cyl with the .218 Bee rifle chambering reamer, but not to full depth, just the length of my shortened cases.
The loading chute was enlarged slightly for the 25-20 case rims.
Lastly installed the 4 5/8" .22 old model barrel.