Thanks for your compliments! In the pictures I was using polyfill stuffing, but since then I have removed it and replaced it with polyfill batting (a little bit stiffer and easier to apply to the internal cabinet walls). I've got it on the bottom, back and one side wall of each enclosure.I wouldn't bother with the grilles either, but I've got a 3.5 month old daughter who will probably find her legs within a few months. I have nightmares of sticky little hands finding their way onto those heatsinks, or worse, poking at the woofer itself! Hopefully a grille will deter that somewhat.
Colin