"In the middle of a tear down"
Ok, I have to ask.
Have you shot the gun before you started altering it?
Nowadays,, I see a lot of people altering a new gun before even trying it out. And heck,, I see folks buy well used guns with the idea of using it as a donor for a custom.
But if you actually shoot it,, and discover it's a heck of a shooter before doing anything,, why alter it?
Now,, I'll be the first one to admit,, I like to make a gun better for me & my purposes when shooting. But I've always tried them out prior to any alterations.
And quite often,, I will only add something that can easily be undone. Grips, shims, adjustable sights, grip frames, etc. The one thing I almost never do is swap out springs. I prefer to do an action job to smooth things up instead of just swapping springs. Long ago I discovered that a GOOD and CORRECT smoothing up of an action by a good gunsmith can make a gun feel much lighter than it actually is.
I have some guns that were worked over by knowledgeable gunsmiths,, where people swear the trigger pull is a pound or less. Yet,, when I put a trigger pull gauge on them, 2-1/2 to 3-1/2 lb pull. It may cost more than swapping springs,, but I'm assured reliable ignition.
So,, I was just wondering,, have you given that SP-101 a chance at the range before trying to change it?