Interesting.
Has anyone tried even lower settings than the published ones? I can't remember the flaps up stall speed for a 152 at the moment, but let's say you flew +5 knots faster than that - what would your range be? At some point I'd imagine that the effects of a headwind or a crosswind component would start to effect adversely at such slow speeds.
I know the twin Skymaster drops from 23 gph to about 13,5 gph from 165 knots to 125 knots. That's a lot. But still way above stall speed - how much more range could be had if you dropped it to 90 knots?