That "cumbersome chuck of foam at the neck area" is there to close off the throat area. If you adjust the WV Platinum properly, this bumper touches the bottom of the mask when you are set. I've used the WV Platinum for years and taken many hits to that area - nothing got through to my throat.
I see no value in chopping up a protector just to fit a dingle-dangle throat guard.
Just my opinion.