I would also like to see how small you could push this concept for just heating up a small mug at a time, like 500ml. I haven't had much success with very small hobbos in cold wet weather, but I think this could work and still be very compact. Also, once you've heated up your first mug of coffee, you could maybe drop in a taller pot of the same diameter, once you have coals, even if it sticks out the top of the windscreen some.