Interesting, because none of my decks were designed as quick decks, nor do I find that they play that way. The 120 and 118 are very much stall decks (especially the 120). One of the 105s is power deck. The others are reaction/reduction decks. Yet I believe you play a very quick deck. Surely you're not thinking higher power points implies quicker. But maybe I'm an anomaly.
So you have this desired cost distribution and choose cards to fit it. Very interesting -- and probably a good idea. I have always started with cards I wanted, then checked certain ratios (number of minions/barriers, number of cards playable first turn, ratio of cost three to cost two and cheaper cards, etc.) to modify my deck. And I tend to produce a lot of rather poor decks -- usually because my card costs are out of balance.