Oh you have started something now Vinny!
This is the reason I still shoot my Prosport in its standard stock.
Every PCP I have (or had) lives in a custom stock, but you dont mess lightly with springer stocks!!!! No No No!
I am even putting off using a Bisley recoil pad in case it changes things. As long as I keep my PS central in my shoulder in it's standard stock it behaves, and I can get decent scores when it comes out for the PJ springer champs....usually. I think I had the highest HFT score this year with an untouched Pro sport and a fuzzy Panorama on top.
I seem to remember posts about this before, and it had driven some people to madness.