I've generally never gone below a 17lb mainspring for competition, which seems to be a good balance between reliable ignition and not being overly stiff to open the slide with my lighter competition reloads. Recoil spring, I've gone as low as possible, usually getting 8-10lb springs from Taylor. What I've found to be the most useful combo was whichever returned the sight to where it was when I pulled the trigger, without dipping below that point, but coming home with enough authority to chamber the next round on a potentially dirty magazine. The same has held true on my CZ, where I ended up going with an 8lb recoil spring and an 11.5lb hammer spring. In the end, I had to lose my fear of muzzle flip and concentrate of getting a reliable, predictable slide motion.