I guess I might as well get involved instead of passively reading the forum.

About two weeks ago, I tried Box 1 and, after examining a Gerber breast milk bag, also folded a container with a pleated bottom. Both had many pin holes due to folding. Then at the supermarket I found an aluminum roasting bag. Although they were the large size, I purchased them just to see how they were made. They seem to have some type of rolled weld along the edges and might hold up if rolled around something. However, the size of these bags was way too big for any type of kit. So I emailed the company to see where I might purchase smaller bags. They responded that large was the only size they made. Then I set out to construct a small version of such a bag. First I considered some type of high temp tape. The tapes I found will withstand around 2600 F but the adhesive backing only about 600 F. That company did, however, make a high temp cement good to around 2600 F which IIRC came in a tube like one would use with a caulking gun. The tube of cement ran, I think, around 40 USD. I think, the only way to heat water, etc. with a small kit is to house the kit in a metal container which can also serve as a mini pot.