[mwebb]

..."(1) the actual mass movement of the exhaust-gas "slug," at about 300 fps,"...

i always assumed the speed of the exhaust "slug" column would change based on RPM and load ......

are you saying the speed is a constant ? 300fps more or less ?

i have a box filled with under reporting MAF sensor s which could be used to provide a waveform ,
which will no doubt be different than the pressure differential sensor and the actual pressure transducer
i am using now

sometimes
i use a venturi adapter connected to the measuring devices and sometimes
just a tube in the tail pipe

sync is all over the place ,
it is a huge problem .
sometimes i need to create a problem to measure the delay before continuing ..... to build in a little kentucky windage to the test results

using a MAF sensor the speed of the column would have an effect on where the waveform occurs in relation to whatever engine event it's synced on
if the speed is constant
it would make a difference ....it would be easier

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also assumed the OP was seeking optimum efficiency at cruise as opposed to MAX horse power at WOT
so exhaust pipe ID requirements should be very different ....