Well, the suspicions were verified. As I've increased my cadence, the cassette makes less sense. I've changed to the 38t front and the 11-28 8 speed rear feels too far apart.

Used 38t and gears 1-4 today to get up to about 19mph.

Now I think about a 32t front and a 12-25 x10 rear might be good.

Can definitely see how a double up front would be good in such a setup too, if one gets much stronger than I am, rides faster, tucks.