Just wanted to update this question with some considerations based on input here and elsewhere.
I'm finding out that the 1911 allows quite a bit of fiddling around with different parts and springs. Not only does the recoil spring affect recoil (duh) but also involved are the hammer (main) spring weight as well as the shape of the bottom rear of the firing pin stop, oddly enough.
As a baseline, I am going on the assumption (trying to confirm with Springfield CS, direct) the gun has a 16 lb recoil spring and a 23 pound mainspring, and a radiused firing pin stop. Comparing the specifications for my preferred ammo options, Federal American Eagle 230 FMJ (AE45A) and Personal Defense HST 230 (P45HST2S), both cartridges are listed at 890 f/s and 404 ft lb of energy at the muzzle. So perhaps I don't need to be looking at a heavier recoil spring, just for shooting JHP.
As to +p, I think "for me" the advantages are more theoretical than actual. I'll still need a center of mass hit on the pin, and having 10% hotter ammo isn't going to help me do that, despite having more momentum (mass x velocity). The additional wear in my gun I am not sure is worth it. And +p will increase my split times. Lastly, I can practice with AE and save the JHP for the match, Since the two rounds, AE and HST, have identical ballistics (providing my gun runs JHP, of course) once I develop an index where to hold my front sight dot (I have a Dawson FO installed), I can do that consistently.
What was really interesting was the FPS, though, and the geometry effects of the flat bottom vs curved firing pin stop. The stock part in the Garrison is a rounded bottom. From what I can tell, a 5/64" radius was added by JMB to address Army concerns and lessen the force needed by GIs to rack an empty pistol in WWI? At any rate, I read some more articles and it appears the installation of a square bottom FPS (properly radiused and fitted) will delay the slide movement just enough to allow the bullet more time to exit, with a side effect of reducing perceived recoil...I may not be 100% understanding all this, but that's the impression I got.
Based on that, I think at this point I'll leave the current main and recoil springs as is, and order a square bottom FPS to fit and install. I'm looking at either the EGW O/S or WC Bullet Proof part. I will then see how the gun tracks with that one change, THEN assess any recoil or mainspring changes, such as the below WC spring kit.
https://shopwilsoncombat.com/SPRING-...ductinfo/324G/
If the results are satisfactory, I'll get a box of the JHP and verify it runs. If that all works out, I should be on the way to an effective setup for pin shooting.