JLD
When we would make something round such as roping reins, draw reins, or head stalls. we would decide how much we wanted rounded. Then find the center of the strap and punch a hole at the beginning and the end of what ya want rounded. We then used a string cutter to split they strap from start to finish. You could use a crown splitter or just a knife and a straight edge. I would then glue and stich the two pieces flesh side to flesh side and then use a edger to round the corners off and run through a rein rounder.Hope this helps
Mike