Good luck with your problem. Not sure if I'm going to be much help. I took a class years ago that specified how many square inches you can leave open with the different batting. We didn't cover high loft. However, low loft poly can be quilted up to 4-6" apart, hobbs heierloom cotton blend can be quilted up to 3 1/2" apart and quilters dream cotton can be quilted up to 8" apart.
I'd almost call my LQS and ask what the recommended quilting is for high loft batting. That way you'll know for sure.