Just as a quick update: We're stuck in balance purgatory.
The rotator went out to my regular balance guy almost a month ago, and he ran into an issue getting the crank to come into balance--the balancer was telling him he needed to remove metal where there was no metal to remove. Hence, he (/we) sent the crank out to another local shop to have the rear counterweight machined and to get the "dog ear" removed from the flywheel flange to try to get it to come into balance.
Gotta be honest, not real happy about this--it's not uncommon to run into balancing issues when you have a heavy reciprocating assembly, but this one is actually lighter than usual, so the crank should've been a breeze to balance. Once I hear back from balance shop #2 I'll post more updates.