How To Make Your Gas Table Burn Cleaner and Safer!
I've worked a lot with propane and flame effects and have a few tips that might make your table cleaner and burning and safer. Generally, soldered copper joints are not allowed to be used. Flared connections or brazed joints are recommended with copper.
Also, you can buy a small venturi valve/air mixer valve that you place inline before the propane enters the actual fire ring. Propane burns at a concentration of 2%-9% propane-air, so it would burn a lot cleaner if it could mix with air before actually being ignited. The result would be less soot, less CO, and more efficiency with the propane.
For the hole sizes, generally 1/16" holes are enough, placed about every 1.5-2" around the ring. An adjustable regulator at the propane source would also be a good idea, since the pressure in a propane tank is around 120psi, and you would not generally need more than about 5psi.
Love the project overall, and will probably make one soon.