4.2 gallons per spec, including the reserve, which is 1.6 quarts.
Other B4 owners have claimed mileage of about 40, with a similar setup. So, I figure I'm close. Known to be a touch rich in places, it makes sense.
As I said, I'll bring a tube, or maybe a 1 gallon spare gas can, just in case. I'm continuing to try and research the gas station issue, it only takes one gas stop a few miles in from either end and I'm good.