[Skulemate]

Well, your setup is better, but still not quite enough. The cylinder should work well enough like that, though you are still going to get a fair amount of restriction moving through it. Why not use a tee instead of a cylinder with two fittings? Furthermore, with only one tube all you've done is measure pressure at one point, before the block. What you want to do ideally is have two tubes (cylinders) directly before and after the item tested, in order to get a pressure difference. Maybe something like I've shown below would work.

Blackeagle: It's hard to find pressure gauges that are accurate enough to read the low pressures that are present in our systems... the ones that are good enough are fairly expensive. Hence use the tubes, since they're much cheaper (though not really suited for use aside from testing).