Removing the chin flap does not make it easier to open your mouth. It makes it fit better, its lighter, and cooler. Going to the next bigger mouthpiece makes it easier to open your mouth. Try this:
1) Put your index finger, in a horizontal position, under your chin, then open you mouth. Easy huh...
2) Now put your index finger just above the your chin.apply a bit of pressure, then open your mouth. Is it not a bit harder to open your mouth in that position?
When the chin flap is removed from the Hybrid, the pressure from the lower straps are now bearing on that point right above your chin. I have removed the chin flap from both of the mouthpieces that I use.
So far I have not been too congested to use the Hybrid. I have my 'curve' modified large mouthpiece in reserve.
Does anyone want to trade for an unused small mouthpiece and an unused small pillow set?