Alright, here's where I landed.

Since the truck was with them already, I went ahead and let them bleed the ABS system. Between the additional bleeds and adjusting the rears and the push rod, the brakes are golden! I know there's speculation that the stock master cylinder doesn't have what it takes to drive the larger calipers--from what I can tell right now, that's not the case. My brakes are nice and stiff now, and engage right where I'd expect them. Could a bigger master cylinder further improve the brakes? Maybe. But I'd say the TBU with 231mm calipers is just fine with the stock one.

Thanks everyone for the suggestions and the sanity check!