BobS, I want your Thermette, too. I think it may be a great companion to a solar oven for the reasons you cite: when you are in a hurry, at night, and when there is little sun.

A thermette is pretty bulky, too. Folding solar could give it a run for its money.

Almost all solar ovens can at least pasturize water [?160 degrees?]; better ones - and that's my goal - can get well over 250 degrees.

Plus, unlike a Thermette, solar ovens can do their thing unattended for hours; do not require finding, igniting, or expending fuel - ever; and do not advertze your presence like a fire either while in use or after you have moved on; and can be built from found materials. They probably could make a mean signal mirror.

All of those virtues convince me solar is worth experimenting and investigating as another layer of redundancy and self-sufficiency.