OK as promised cardboard oven experiment, my wife found me some monster skewers the rest is cardboard with tinfoil stuck on with PVA glue, I've had it up to 200C with a trangia burner in the bottom, it's just a matter of leaving enough ventilation and you can use whatever you like so long as it sits in the bottom ( not in direct contact) most camp type burners will do or hot coals in a steel bowl. Sorry it's sideways
view from inside with the top pieces visible - see how you adjust the heat?
And rolled up for transport
I have a strategy, it's not written in stone, nor can it be, this scenario has too many variables, everything about it depends on those variables, being specific is not possible.