You can shave a bit at a time from your original spring to get the weight you want, but the problem with that is if you shave too much, you can't put it back. So it would be nice to have a spare or two "just in case". There was a brief time (a couple of months) back in San Miguel when I first started accompanying the U.S. Consul on his Colonel Work that I occasionally carried my 1911. I had an original Dan Blocker shoulder holster for it, and always made sure the Colonel knew when I was carrying it. If he didn't think we'd need it, he'd say so right away. If he did, he usually also had his 1911 from the World War (II), so he would carry his as well in his own Galco Miami Classic. For an old guy, he was cool.
Dressed for Colonel Work in the mid-1990's with my 1911 .45 in the Ted Blocker holster. The 1911 in .45 ACP is prohibited for civilian use or ownership in Mexico, and Colonel Maher wanted to move us away from using them. I was not a part of his wheeling-and-dealing with the local Mexican Army General, but suddenly one night he appeared with a S&W Model 6904 for himself and a 3904 for me and told me that those were what we would use from now on. So this .45 I had, became more of a liability. The slide, from my old Manitoba IPSC competition gun with the Bo-Mar sight mounted by Murray Gardner's gunsmith from Gun's 'n Stuff back in the day sits now in the Queretero Custom Shop to be used as a sight-install guide. The frame was later cut for a Clark/Para ramp barrel and with a .38/9 ejector and a new slide it because my .38 Super (and with a second barrel, .380 Super Cal).
Anyway, I bring all this up because I had whittled down my own mag-release spring using a dremel tool until it was "just right". I was showing it off to the Colonel one day out at the range, and he asked me "If you set the gun down with the release button pointed downwards, can it accidently release the magazine on you?" I laughed it off, but it made me a bit paranoid. The Colonel had been on Saipan and Iwo Jima and he had killed a Japanese soldier at close range on Iwo, and he wouldn't have asked me that unless he thought it was important. At home, with the gun unloaded but with a loaded magazine in it, I set it down deliberately a bit heavy on my wooden table covered by a thick Mexican tablecloth. One out of three times, the mag would release.
It took about two months from me to get a few springs sent down from the U.S. because I had to order them through other people and by that time, we were no longer using the 1911's. But by the time it became my .38 Super/.380 Cal it had a heavier spring in the mag release. Anyway, that's my system for checking the mag-release spring weight. If you can set the gun down heavily, can it release the magazine unintentionally? You may or may not care.