I already have a separate manometer that I've used for some limited port velocity testing, so I'm good there.

I haven't decided exactly what configuration I'm going to build; I have a couple of different approaches in mind, neither of which are that complex. Regardless, the total cost to make something functional should be far less $$$ than what the commercially available carb flow-test fixtures would cost to purchase.

Also, I have an idea or two from some stuff I've read that makes me think using a fixture that bolts directly to the deck of the flow bench isn't the best way to test. Instead, locating the fixture on top of a cylinder head adapter of adequate bore size (looks like my 4.375" bore adapter is about right) to give the carb something more akin to an intake manifold plenum to discharge into before dropping into the flow bench's "black hole" is supposed to be better for pressure recovery characteristics.