Well...
I have a desecrated Webley Mk. VI, 'Percy,' with the cylinder milled, shot him with authentic half-moon clips, which worked fine, and full moon clips, which worked fine and held up under more shootings. The cases eventually ruptured--news flash! .45 ACP cases are NOT the same diameter as .455 Eley! You can, however, sayeth the folks on Gunboards, fire-form .45AR into something that will size in Eley dies. I have a 100 rounds of that for experimentation.
Starline brass is making .45AR. To shoot the Surplus Special 'authentically,' I suppose I'd see what load comes close to duplicating 1918 spec .45ACP. For fun shooting, I'd probably use the Starline brass and lead SWC and see what happened.
This September/October 'Handgunner' has an article by Charles E. Petty saying it doesn't matter you shoot in a .45ACP wheelgun--it won't hit it. I hope that's not borne out by my own experiences.
Best!