i don't think that the leading edge needs to be exactly the same. back in the days when i bought kits, i used a large sanding block and just a few cardboard cut outs to get the leading edge about right. after the basic shape was correct i'd simply sand until even and that was it. i was definitely not into scale or exacting standards but the planes flew well and really never needed too much adjusting. now there are sanding blocks from tower that have all different leading edge shapes built into them. but back then i did fine with a block of wood and some sand paper.