I didn't see anyone mention the Gotvapes air controller so I will. It's cheap, $3.45, and you can tune the draw on your ProTank, and many others as well, to your precise requirements. It is in fact made specifically for the ProTank and fits it exactly. Got mine drawing exactly the same as my Vivi Novas. Love it.
How does this contraption work? For the laziness in me today.