I don't see a single "best" way here, just what works for individuals and their respective goals. Actually, this ain't a bad thing.

The last time I rode into a strong wind (15-20 mph), I initially tried to keep my speed up for the first seven miles. Then I looked at my HR - way above my LT. I essentially kicked my own butt...I was doing a longish (for me) ride, total 47.6 miles, and did the last 40 in recovery mode, with about the last ten in the tail-between-my-legs mode. Now, if I'm going on an "endurance pace" ride, I watch my HR and let the speed be what it is. If I'm doing VO2 max intervals, I don't care about the wind. On both, I spend most of the time in the drops at a relatively high cadence.