Here's a pic of my setup:
http://phaestus.procooling.com/test_setup.jpg
Just a big ball valve and some 1/2" NPT x 5/8" barbs. The flow meter has the same in it now (at that time it was copper pipe reducers). I think that the ball valves and this flowmeter might not be good enough for real precision work, but for the kind of data I just presented above it works fine.