apperently they only do 57 % from what ive read there was only a few old wilwoods that shut off completly
lol not being funny but its one line in one line out how could u not plumb in properly ?
Well it should be 2 lines (front corner -> rear corner), and if you've put the valve in backwards (depending on design) it might cause unpredictable behaviour.
The rears should only account for about 30% of braking (with no additional weight on the rear axle).
All I can go off is what you have described, you're saying if you shut the valve totally - they still lock up - that screams something is fatally wrong.