Short burn cycles (2 to 3 hours) are causing me to think about replacing my F3CB. Are there any similar sized stoves that provide longer burn times? I imagine I need to upgrade to a stove with a larger firebox. Due to installation situation I'm gonna need a stove where the horizontal exhaust pipe is no taller than the F3CB (which has a height of 22 9/16" to center of vent hole). I could use one slightly shorter as I can simply shim up the stove.