Looks like fun!
When I tried my newly made J-hook for the first time with my 36 caliber Uberti Colt 1861, I noticed that the lower rear end of the grip touched the back of the stock, so I added a weld about 1/8 inch thick. It worked, but does not look nice, but the added weld cannot be seen when the J-hook is in place, so I'm happy. I have a 5-1/2 inch long 1851 barrel on order for the 1861 36 caliber revolver shown in the pictures. That will "convert" the 1861 to 1851, yet still allow me to use my 1860 detachable stock (with short J-hook), and my stock has not been modified in any way, and still works in my 1860 Colt when I use the original J-hook.
I plan to shoot it soon.