Members with 4 wheel disc systems: Can you lock your wheels?
I do not know what the problem was with the Hydroboost you tried. I have two friends, brothers, that installed Hydroboost on their '57 and '58 Chev p-ups and they worked great.
The pedal has full travel. I've ran hydroboost, manual and vacuum boosted setups which required bleeding each time. The pedal goes to the floor when the bleeders are cracked.