my training was- if a high pressure pressure bottle falls and the fitting breaks...... jump on it and ride it like slim pickins yellin yeeee hawwwwww. i checked my victor book a size 2 tip for welding 1/16" to 1/8" o2 pressure= 5 psig, ace pressure= 5 psig. for a #4 for 3/16" to 1/4" is o2= 10 psig, ace= 7 psig. in fact size 000, 00, 0, 1, and 2 all call for 5 psig of each ace and o2. but i'm sure most everyone just about what ever you set it on the actual adjustment is made at the torch. in fact you can open the torch valves and do the adjustment using the gauges so it prob doesn't even matter what you set them on as long as it's enough but not too high to be dangerous.
