You guys... It requires a set amount to begin compressing the spring. Cutting the rod, threading the rod on both ends, adding the nut w/ opposing threads, to allow the wastegate flapper to have less pull against the diaphram, is not going to make the diaphram open any easier w/ less boost, it's just going to allow a less tight seal at the flapper.
say you hit a diaphram w/ 8 lbs of air w/ your air compressor it doesn't open it some, or slowly, it just sits there closed, UNTIL you raise the pressure the exact amount as required to overcome the spring.
If you adjust the flapper to have a tighter seal, and it's got a hard pull on the rod and the diaphram, the diaphram will still open w/ the same air pressure, it just won't open the wastegate as far as some of it's travel is already spent.
That's been my experience dabbling with them, checking the ones I have for leaks, and making a stock t3 diaphram that would fit my hybrid.
Willikers.