I see what you are saying about the blown burners, and no I havn't see many well designed homemade ones. I was assuming the blown and venturi burners to have the same size orifice. If the orifices are different sizes then no, pressure is no basis for comparison. So, assuming that, PSI has everything to do with fuel economy, as the higher the pressure the more gas can be crammed through the orifice until such a point as the orifice goes sonic and no more gas will go through no matter the pressure.
BTW, my burners are venturi burners that I am forcing air into, when the air stops on mine they still run just fine. When I am running my burners (with #65 orifices) at 7psi they are more economical than running them at 12psi (uses less fuel at lower pressure), but I like the hotter forge running at the higher pressure. So if I add the forced air I get the hotter forge at a lower pressure. The thing I am curious about is the other pipe forge I used had #72 orifices, and would run all day long on 4 gallons of LP but I can't get mine to run on #72 orifices.