Here is my mini busbuddy-type stove, fully functional and very hot (top speed = blueish flame at secondary holes...)

2,8 oz.

Small instant coffee can, and steel beverage can as a furnace (Aluminium can melted at first full heat trial mad ).

I didn't test it in the field yet, but I suspect it's quite delicate to use, needs very little wood and constant adjustment and control...

The hole are a bit big, and air intake too powerful.

But it was fun to make grin , and miniaturization works.