exactly...what you are really after is mass air flow. too many get caught up with boost (not a flame, just lack of education for most...thats why we have this site), we should really have mass air flow gauges. when used in the efficiency range of the turbo, a boost gauge is a good tool to guide you. but outside of the efficiency range, the boost rise is just hot air and doing less good than if the boost number were lower (within efficiency).

similiar in a sense is a how a torque wrench gives a good indication of bolt stretch which is what you are really after, not the torque number.

 

An Air Intake temperature gauge would help you tune it. Try to find the spot where the air temp goes way up with higher boost and keep it there. At least that's how I understand it. If you go past that point you're just defeating the purpose of getting more boost.