Tuning with jets, Power valves and an O2 guage

I reset the intial at 17. The advance stops at 31 degrees which occurs just shy of 2000 rpms. This was with the Distributor #1 in the form it has been since 2005. With the orange springs I put in distributor #2, the curve begins about 400 rpms off of idle and ends about 2400 rpms.
Just a question because I really do not know: Besides stiffer springs, is there any way to get this curve a little flatter? I mean even with 2 orange springs it just ramps up so dang steep.