I have been reading Michael Porter's great book on burner and forge design. I am going to build his basic 25-gal propane cylinder forge. His basic design calls for a 1/2" burners for forge diameters up to 6", 3/4" burners up to 9" dia, and 1" up to 12" dia.
For evenness of heat, would it better to use, for example, two 1/2" burners instead of one 3/4" burner?