Vikki,
I have the Accuquilt Go Big. It was a surprise to find some of their tips in the instructions. They do work.
One is to feed the fabric through so the lengthwise grain is in the same direction as it goes through the rollers. That's because the lengthwise grain (parallel to he selvedges) stretches less than the cross grain (perpendicular to the selvages). The trip though he rollers puts enough pressure on the fabric to stretch it a bit.
Another trick I've found to improve stability is to line up the lengthwise grain with the metal cutting edges, not the die frame. The closer a cut edge is to the straight grain line, the less problems you'll have with the edges stretching.
I also stitch with the scant 1/4-inch seam the other ladies have described.
None of this is hard, but it takes a while to make it a habit. Good luck!