The dash is nice and solid now. I did a finish cut with the cutting wheel. and sanded the edges. No more brittle dash. I can hold it in the middle and there is no flex or creaking … FTW! It may have visible cracks but its good enough for me, and it beats not having one. its blinding without one.
After trim, sand, & a wipe down:
Applied the insulation and ready for an install: