Just out of curiosity, is there any aspect of your tune which specifically justifies such a heavy recoil spring?
Interestingly enough, JMB specified a 14-16 pound recoil spring, which is lighter than the 18 which seems to be "standard" for most makers these days, as is way lighter than some extra-power recoil springs.
With something close to a standard tune, most folks would be genuinely astonished at how well a 1911 runs with a light recoil spring.
Also, depending on many variables, many folks find that the sweet spot for shot follow-up (so the spring doesn't force the slide forward so hard & fast that the gun jerks too far down during the second half of its recoil cycle) is about 15 pounds. With my gun, this is ideal for letting the muzzle "drop" right back to its original position after each shot, without too much or too little tendency come back down.
Also, it can be argued that, in terms of battering the gun, the design is optimized for a light spring. When traveling rearward, the slide is halted by coming into contact with a portion of the frame (inside the dust cover), which is specifically reinforced so as to handle all the beating it must take, even with a light spring.
In contrast, when moving forward, the momentum of the slide is finally halted when the barrel locks up into the slide, and the barrel (now with slide locked to it) slams forward into slide stop pin, and the entire momentum is absorbed entirely by just that little pin and its little hole. Eventually a strong spring can cause problems here.