Changing the recoil spring has 1 effect, it changes the slide speed, lighter spring faster, more slide impact, heavier spring slower, lighter impact. A 9mm 1911 is already at some disadvantage, as the cartridge works in a small window, power wise.
In a game gun, sure, lighten the spring, lighten the ammo, lighten the slide, but not for a defense gun.
Now the heavier guide rods, or just adding a guide rod, plays to reciprocating mass. The mass that does not move, the frame and a guide rod if you have one, counter acts the mass that moves, the slide, the barrel moves down not backward so does not have much influence. The mercury guide rods counter act the mass, as the the slide moves rearward, the mercury and balls move forward. I have a Harts in my glock 21, you can feel a difference, slight but noticeable, and a .45 does not have much recoil anyway.
Things that do work, relieving the frame at the rear of the trigger guard and a high beaver tail grip, lowers the bore line for improved recoil absorbtion. A firm 2 handed grip and good shock absorbing stance. Some shock absorbing material in the grip, limited on the Para, but lots available for single stacks. Lighter standard loaded bullets, not Corbon level stuff. Lots of practice and you will never think of recoil again.
Now of course there are exceptions that have more to do with shooter, none of the above is going to help someone with a disability or injury. Even old age and weakness. I have known 100lb soaking wet girls, that shoot box stock 1911's in .45 and can't get enough, it just means that much to them to shoot them well.