I bought some P14 springs and fitted them to my 10rd PT145 mags and 12rd PT24/7 mag. They are definitely stiffer than the originals. They do help.
I started cutting one coil at a time and trying the mags for capacity and function.
The 10rd mags still function best with only 9rds but I discovered another problem while working on the spings. The mag release notches in the factory mags are cut about 1/32 too high. If I push up on the mags function was perfect even with my truncated cone hollow point handloads.
Anyone have a fix for the release notches on mags?