Hi RJ, I have the square high pressure Bayou Classic for my setup, it has 55,000 BTUs.
The guy at the local brew shop told me that if I went with a burner that has a higher btu, that I would have to be careful of caramelizing the wort, ( getting the wort to hot and scorching the bottom of the brew pot )
I would be curiouse to hear what others think about a higher btu caramelizing the wort, thus giving the beer a darker color.
If you can, think about getting a large propane tank, or maybe have two on hand if it's at all possible.
One tank should make 2 or 3 batches, but you would hate to try and squeeze that last batch out and run out half way Thur the boil.
Take care RJ.
stevemwazup