Misconceptions and confusion, I need some clarity!

[vic_dahn]

make a box just to house the motors with closet flanges on each end. 4''
when you want to pull use one end when you want to push use the other. just pick it up and turn it around. you will need a metering device on the end of it to regulate the airflow in or out, you can make a screwjack that mounts to your table that will close off the opposite side of your box (inlet/outlet) to regulate test pressure.

Then the box Can be made ultra cheap, light and effective,

I use this with a pitot fp2.0 I just turn the motor box around and flip the fp2.0 and I have pressure, or vice/versa . the test box houses the head fixture and static pressure readings so the motor box does not need to be a prefect seal since you are only taking measurements after it (in push) and before it (in pull)

Its a little more effort to use but cheap and effective. I use PVC to plumb from the closet flange to the fp2.0,

no floating DP for me