1. I don't think it's anymore fire hazzard if it's attached or just sitting on so lont as it's controlled whith a t-stat.
3. Agreed. Put it directly on the heat source on the outside and then measure the inside temp with a thermometer with a probe directly above the heat source.
6. 4 qts = 1 gal
7. I agree that heat tape is pretty darned good; especially price wise. But there are UTH just as good. I know some people just feel safer using a UTH; which I think is fine so long as you use a high quality one.