on the link Susan mentioned, I posted that I had opened the hole on a new surplus Swiss Ranger Volcano stove to allow a Trangia stove to fit... later enlarged it so a Sterno can fit... at that point you are about at a full diameter opening...the jelled alcohol in the Sterno seems like a good idea for a car stove, and can always use twigs...at the time you could get a pair of units from Sportsman's Guide for around $20