MS, what kind of Gravity feeds are you using?
I use squeeze bottles for my mixed paint, after I'm done mixing the paint I take a small amount of panty hose to use as a filter and put it across the top of the bottle, l lay it down flat and use enough that it will cover the threads, screw the top. When you have to squeeze really hard, you know its time to replace the filter. It keeps all of the big chunks out of the airbrush.
Use a big syringe to accurately measure the paint.
Epoxy Syringes