As far as know, the holes have nothing to do with draw tightness or throat hit, that all depends on your carto, liquid, and sometimes how tight you screw it in to the battery. Hole size only determines how much, and how fast your tank lets liquid into the carto. I have slots cut in mine that only allow liquid into the carto if I take a good hard draw without firing my battery. That way I can control exactly when and how much liquid I draw into the carto. I'm pretty sure the size of your holes doesn't effect your draw or TH.