Any question answered...

I had assumed (I presume incorrectly) that avid speed dials could be adjusted to suit mini vees with their adjustable cable pull doohickey. Was I way off base here or might it work in a pinch?

You were incorrect, in the sense that even dialled down to minimum pull a Speed Dial will be pulling considerably more cable than is needed for road calipers/cantilevers/mini-Vs. For somebody with strong hands they might be tolerable, but may not pass the EN14764 test requirements in respect of stopping distance with the specified lever actuation force.