Want to build a bike and I got really interested in the cafe racers and I want to see what a could do to start

So been wanted to build a cb 350 or cb750 but I dont know what frame to start from and would like any advice via /r/CafeRacers https://www.reddit.com/r/CafeRacers/comments/dqexl4/want_to_build_a_bike_and_i_got_really_interested/?utm_source=ifttt