Thanks to this forum, Rich Harman and David Somers in particular, I combined your ideas for this new grid for my laser that tested out perfect.
Made from 1/8" Duron HDF - 35.5 x 47 x 2", all cut on the laser, and glued with gorilla glue. I made diamond shaped holes in the 36" dimension to run 3/8" x 3/8" steel square rods .10" under the surface for magnets to grab. I ran the square stock at the diamond cross section so that the laser doesn't flash up off it. Before I slid them into the grid, I ground the top edge to a sharp knife edge to reduce flash from the narrow arris on the hot rolled steel.
It cuts acrylic without any reflection flash at all, is dead flat, and magnets hold better on this grid than honeycomb with egg crate. No detectable wear on the edges either - should last quite a while.
I could still install N52 magnets within this grid if I wanted as well. Thanks for the source - kjmagnetics.com Grid-noFlashCut.jpgGrid-clsp.jpg
If anyone wants the dxf file to cut their own, PM and Ill email you the cut files.