I have an old Mr heater sunflower style propane tank top heater that I want to use with a 5 lb tank for a hub style shelter. Does anyone use this type of heater in their shanty's? I know they are for outdoor use only. What about opening the vents on the shanty? Years ago they used them with 20 lb tanks in homemade shanty's on Lake Erie and there was never a problem. Thanks everyone.