Order the quart unit size, i.e. one quart can of each part. I figure six bows per quart size unit, but I tend to waste a bit, plus some of those are four or even five lam bows with power lams, so they take a bit more. I use the "glop" or "blob" measuring system and try to get a bit too much mixed so I don't end up re-mixing in the middle of a layup.