4 Wheel disc, soft pedal

I've been fighting a soft pedal all year, there's air in the rear brakes, but they bleed completely clear.

Car has new front lines/braded hoses, all three rear hoses are new(rubber) and new lines. Only original line is the steel one front to back.

Front is new 11"/2.75" rotors/calipers. New 15/16" M/C. All from Cass. Drum/Drum Distribution block.
Rear is a right stuff 11" disc kit. I didn't want parking brake provisions, and they were the only vendor to offer them that way.

I've bleed the brakes the regular way multiple times, vacuum bled them multiple times, and just recently used a pressure bleeder. I've taken the calipers off the rear brackets, I've angled them every which way, they always have a stream of air free fluid.

I'd swear at this point that it's just how the pedal feels on a 15/16 MC, but if I pinch off the rear hose, the pedal instantly gets better.

Two questions.

1: What's the normal pedal travel on a 15/16" M/C?
2: The few people who've bleed these successfully, any tips?