I'm thinking the WB is MUCH OR critical of exact hand placement on the bow than standard or drop away rests. I get tight groups that vary in a 3" circle or so depending on how EXACT I replicate my hand placement. I suspect it is due to the full capture nature of the rest magnifying the slight inconsistencies...
Absolutely! A full capture rest like the WB is definately more critical to hand placement/hand torque than a conventional shoot through rest.
I look at it alot like brace height and the longer the arrow stays on the string the less forgiving to hand torque. The longer the arrow stays in the biscuit the less forgiving to hand torque.
Try mounting the biscuit as far from the riser (against conventional wisdom) as you can and see if there's a difference.