Very nice bike, racer. Welcome to the forum.
Use the Google Custom Search feature and check out what others have done for custom exhaust systems. 1/2" or 3/4" EMT, electrical conduit, lends itself well to making a system that will fit your frame. The issue with the upward slant to the muffler is that it will soon clog with oil than can't be blown out and will pool at the low end. Another reason it's not a good idea is the potential for burns.
Thanks for sharing.
Have fun, ride safe.
Tom