I think my husband bought the fiberglass mesh for a pick-up truck bed repair project a few years ago. It's been lying in wait for a new project. It was throwing a lot of warmth, and the one ounce of fuel I used seemed to last a little longer than it does in my old standard simple Fancy Feast stove. We have winter in the forecast again, so I hope to take it for a proper field test this weekend. I'll definitely report back.
I saw a You Tube video where Hiram Cook used felted wool for one of these stoves, so I imagine that fiberglass insulation would work too. Here's a link to the wool stove build:
https://www.youtube.com/watch?v=kjIewnxgPHsMethyl Hydrate seems fairly common around here and in all seasons. All our hardware stores and walmarts seem to carry it. It's cheap too, especially compared to Heet, which seems to only appear on the shelves in the winter.