Check your charts for tip size as suggested. Most tips up to #3 will work fine with no more than 5-7 PSI on Acetylene. Oxygen is more dependant on pressure than the acetylene as you need to adjust it for the tip size, the acetylene can be adjusted with the flow valve regardless of the pressure but dont exceed 15 PSI as previously stated (there is a reason the gauge is red past 15), but the O2 for the high pressure cutting cant be set with a valve, it has to be set correctly at the gauge to get a good cut. Anything up to 1/4" can be cut with a 00 tip and about 25 PSI on the O2. 0 tips for 3/8 and 30 psi, #1 can cut up to about 3/4" and 40-45 PSI and still only need about 5 PSI on the acetylene. Too much gas and you will be melting the steel prior to getting the Oxygen to it to "cut" it.
Popping is usually caused by getting the tip too close and sparks getting stuck in the holes from dirty plate, OR by air leaks either at the tip or more likely at the mixing barrel to cutting head connection. I just replaced the dual O rings in my cutting head at $2.50 each from my local welding supply. They were so hard that they no longer sealed properly. With new o rings, dont overtighten, 2 finger tight is sufficient to seal the connection.