I have some thoughts on how to avoid the cotton candy issue, like making shorter pieces so the bit doesn't heat up as much and gets lifts out of the groove frequently, or erasing very small bits of the edges and adding a separate "path" to split up the long cuts and to get the bit to lift out periodically. I will also try to cut through the foam (getting the full 2" is a challenge) so that the cutting dust will fall out of the slot, and I can add tabs (an auto function) so that the pieces remain attached.
Also, with some wheeled guides on the sides, I can prevent the sheet from skewing (which is
very important for the accuracy of the pieces) AND it will let the bit only cut on the bottom inch or so. ALL the cotton candy globs are forming at the top of the flutes; when the cut strays from the first groove. I'll clean the filter in the vacuum (it is central system) so that there is as much velocity from that as possible.
Here's some pictures of the F1 section next to my Scion xA for a scale comparison:
