I would increase the heck out of it. 9x23 is crazy hot. We had a 24 pound recoil spring in a Commander we built in 9x23 and we could have gone with more. I would say, start with an 18.5 pound spring and work up from there.
^^^Thks for the info! I was going to contact SA custom shop and see if they could help me out with this project. It would be cool to be able to shoot 9X23 out of the a converted Range Officer 9mm. I have boxes of 9X23 I need to shoot up