I'm not sure how you got that point down with a check valve on top of it, apparently you didn't beat on it too much. Eleven gpm is pretty good, depending on what kind of screen you used. There is a large difference in types and brands.
The tee, gauge and ball valve is the easiest method to check your flow and pressure. Once you determine the flow, don't forget about friction loss through fittings, pipe etc. The pipe size and number of fittings can really drop pressure if you don't design it carefully.