if it helps any i find the males of certain morphs to be more affordable than the females. So if you are wanting to make bees (which I assume by your wanting to pair a spider with a pastel) buy the female in the less expensive morph and the male in the more expensive. I bought my male spider and female pastel. The pastel is usually not as expensive, pastel female was much less than a spider female.

with pieds i would buy a male pied and a female het pied, or just the 2 hets as you stated.