try a couple concave fillers and a return to cylinder kit i have 2 N7s 2 with sunnybrooks with all forward bars and one with a stock rotor with 2 reverse all have shimmed helicals and green stem kits w_choppers august wieser rosholt, sd
I like having all reverse bars out especially if using peg retainers. You can use a couple old worn forward thresher bars cut to fit in place of reverse. Good luck with your project.