What's the deal with you folks only loading 30-50# loads of wood in this furnace? It's 4.1 or maybe 4.6 CF right? Heck, I load 45# of low density softwood into my 2.8 cubic foot firebox every time. Is it because of that silly metal curtain thing that hangs down blocking half of the loading door? Does that thing prevent a full fill of the firebox?