Same answer as for the same question asked by the same guy on GT. There're no 9mm loads that would be too stout for a 20# spring. (But it wouldn't cost too much to try a 22#, also)
I don't mean to be overly acerbic, but it would seem to me that if you are sufficiently ignorant about the manner in which a Glock works, such that you would ask a question like this, then why would you think that you are qualified to fabricate your own recoil system? This is befuddling.