Factory spec is 16lb recoil spring and 23lb mainspring. Where you go from there is up to you.
However, the first thing I'd do is what gaijin suggested; fit a flat bottom firing pin stop. I use
EGW stops. After you do this put a few rounds through the pistol to see what effect installing the new stop has had.
I suggest shooting with your weak hand only during the testing phase. Shoot slowly and deliberately. Your objective is to observe the functioning of the pistol. It is not to throw lead down range as fast as you can. Nor is it to determine how accurate the pistol is.
You can test how light a recoil spring will feed rounds from the magazine without firing a shot. Fill the magazine to capacity, lock the slide open, insert the mag, drop the slide using the slide stop. Start with the lightest recoil spring and work your way up in spring weight until you get 100% feeding from a full mag. I'm of the gaijin school of thought on recoil springs; I use the lightest one consistent with 100% function and how the pistol feels as I shoot it.
It wouldn't surprise me if the pistol will chamber rounds with the very lightest spring but you probably don't want to run it with anything less than a 12lb recoil spring. So, I'd suggest getting a 12, 14, and 16lb conventional recoil spring for testing. Once you decide which weight recoil spring of the three works best, move on to the mainspring testing.
As has been pointed out, the heavier the mainspring, the heavier the trigger pull will be. But you'll have a tough time discerning the difference in trigger pull by going a pound or two above or below your starting point. Assuming the mission of this pistol is personal defense and not competition bullseye shooting, a 5lb trigger pull is perfectly fine. What I'm saying is, don't be too concerned about getting a heavier than 3lb trigger pull.
As you know, the other effect of using a heavier mainspring is that it slows down the rearward velocity of the slide. I'd much rather slow down the slide than have a 3lb trigger.
Keep swapping out mainsprings and test firing until you find the one that feels the best to you and allows 100% functioning of the pistol. If you go too heavy, the slide may be slowed so much that it doesn't travel fully to the rear resulting in bolt-over-base malfunctions. If you go too light, the slide may slam into the frame hard enough to cause inertia feeds. The Goldilocks principle applies here.
Change only one thing at a time so you can isolate and observe the effect.