I get the non-steady air intake flow situation with its "square wave" characteristic. (See reply #41) Further, I imagine that muffler pressure is a damped version of same, out of phase by ~140 degrees.
Since viscosity is the measurement of resistance to flow, and the simplest viscosity measurement is a gravity drain-down procedure by convention, that is a good starting point. Determine the characteristic of a fuel mixture and it's temperature sensitivity. If it is only a few percent over the temp range likely to be encountered during one run, then the system should not be so critical as to make the whole bus fall off the cliff.
Would also be interesting to scrounge up a low mass TC and insert it into the tank outlet and see if the temp rise is significant. That would back up any calculations. My gut feel is that the heat content of one tank volume of displacement air will not be greatly significant--but there are neither calcs or tests to support that yet.
I will keep thinking about it.
Dave