SPud,
May be a question you had rather not answer,since kind of dipping into your business. If so more than understand. I am working on a fuel pump testing set up. Nothing fancy just a way to keep up with pump. I have good supply if fluid gauges from my Test and Balance business,been doing air and water flow testing most of my life.
I am thinking a simple setup with motor to spin pump at variable speeds,check pressures and compare to on regular bases. Will be using water since its just a comparative number and not actual flow number. I have some commercial flow measuring devices(circuit setters mostly with dial gauge) and will check flow at set pressure also again just comparative.
Any reason I will be fooling myself on results or suggestions as to how to make a more accurate design.