I don't necessarily know how to replicate the original look, but, I really can't stand those original stovebolt screws/bolts! I just pulled another one out of my frame yesterday, and replaced it with a machine screw. I totally get the antique aspect of retaining the original look/design, but I don't have a fulltime mechanic working on mine- I need to be able to fix it myself!
Best of luck in finding your desired path forward.
Regards,
PM