Very good question. Personally I haven't with the brand you mentioned. I did make a few calls to some peeps. They all said the same thing... You need to tweak (adjust) your ratio (foundation:244) to the consistency, coverage (sheer / full) you want. Typically, one or two drops. Then there is the reload factor to keep your mixture consistent, even from empty. So in essence, it's trial-and-error... I know it's not the hard answer you're looking for, but well, y'know, airbrushing...