All I can say is to play with it.
I was able to set the second-stage trigger on my GPR 50 cal. to a break point that my brother calls a hair trigger. After pulling the rear trigger for the take-up, all I have to do is breath hard on the front trigger for it to go off. The result is a BP rifle with more accuracy than I need - I also went "non-traditional" and installed the Lyman peep sight on it, extending my sight plane by about a foot. That didn't hurt the accuracy either. Believe it or not though, the intended use is for deer and javelina, not target work.
Experiment with the set up before you reinstall it in the stock. I don't think you will break it, and I am sure you will find a sweet spot in it for yourself. By the way, I'm working on a 54 cal. GPR right now and will go through a similar process once I get the stockwork completed on it.
Good luck, and let us know how it goes.