Anyone running a WR 450 cartridge ?

I'm looking at buying a Westley Richards rifle in one of the 500/450 variations
Not entirely sure exactly which one of these it is

Just wondered who's also running one of these and what issues in getting brass and what bullets you prefer
I can always go the paper patch bullet route because I have found it pretty effective in my 500 2 5/8" BPE and hope they also work well in my yet to be fired 500 3' BPE

This cut and paste from Cartridges of the World

.500/450 No. 1 Carbine .500/450 No. 1 Express .500/450 No. 1 Musket .500/450 No. 2 Musket
Historical Notes:
Perhaps no cartridges in the world are more abundant or more confusing than those of British origin labeled .500/450 and followed by one or another designator. There are no less than 19 listings of individually identified cartridges in Bill Fleming’s British Sporting Rifle Cartridges. Many of these cartridges were loaded with a great variety of bullet weights. All of these were bottleneck cartridges, and all originated with blackpowder loadings. The No. 1 Carbine was Westley Richards’ first drawn-brass case, which appeared just
before 1880. W-R was also responsible for the Musket and the 23⁄4- inch No. 1 Express, and possibly others of this lot. The oldest of the .500/450s used a coiled-brass case of 21⁄2-inch length, dating to 1871. Some of these cartridges were loaded well into the twentieth century.
All of the .500/450s are in the same class as the .45-70 and would be fairly effective short-range cartridges for North American game. Because of the great variation in designs, the handloader should be
General Comments: careful to determine exactly which of the many variants he has before attempting to build cartridges for it. The company CH4D (www.ch4d.com) has a large selection of .500/450 die types in
stock.
.500/450 No. 1 Express Factory Ballistics .500/450 No. 2 Musket Factory Ballistics