I have a lot of fun with my S&W M57 6" with hardcast 210-215gr SWC sized to .413" (WW+2%tin) at approx 850-900fps with 700x, Unique, Universal, or AA#7.
I presume your bullets are commercial-cast, so are prolly .410". Since "fit is king," I think you should use them for high-power stuff, so you might be able to "bump 'em up."
Rugers quite often have a tight spot where the barrel screws into the frame, so you might use the more-powerful load to try to keep the barrel sealed. Keep an eye out for leading, tho'.
I use Herco, 2400, and AA#9 in that range. Alliant MP300, H110, and WW296 are also excellent.