Some hats don't chick well, irrespective of weight ratios and distance between the cymbals on the stand. I don't really know why this is but I've certainly owned plenty of high end hi-hats that air-locked constantly and didn't have a good foot sound.
I play a pair of Istanbul Sig 14's, got them used, and the bottom hat is very slightly warped. They chick perfectly, and never ever air-lock on me. I think the warping is actually beneficial in that regard, because other than that I'm doing everything wrong and they should lock constantly by the conventional wisdom. I like them very close together, and their weight is very similar, and not heavy. I've had some Sound Edge and Mastersound cymbals too, and my theory is that symmetry in the edge warps negates their benefit. A warp on one edge only keeps the air moving well.