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It won't be significantly different with a powder that lights as easily as Tightgroup.
Unclenick is the ultimate thread-killer
. Once he speaks, there's little else to add. As usual, he pretty much covered it this time too.
I load quite a bit of 45 ACP, but the closest thing I come to your loading (185/TiteGroup) is a 200gn FMJ (X-treme plated, actually), using 4.8gn of TiteGroup (large primer) - chronos @ 840 f/s through a full-size 1911. If I were to "convert" it to a small primer, I would do just what Unclenick said: Load the small primer brass with the same 4.8 grains, and past them over a chronograph. Adjust as needed.
As an aside: I like your load combination of 185/TiteGroup. Small or large primer, it should work well. TG is a good choice here. It ignites easy (as Unclenick mentioned) and that bodes well for light bullets. Personally, I'm partial to heavy bullets and guess what . . . I
still use TG. My go-to plated range shooter is an X-treme 230 PHP (plated hollow point), using 4.6 grains TG - fairly spunky at 807 f/s.