Schrader Valve on fuel rail

[BigMac76]

Ok guys, when I bought the car it already had a fuel pressure cutoff switch for the nos and had the schrader valve removed. Thinking I might be having pump issues and am going to be adding a tee into the mix. Also very interested in maybe adding an inline fuel pressure gauge so I can monitor it pretty much at anytime.

Any suggestions or should I just add the tee and add another schrader valve in place of the old one that was removed for diagnostics instead of the guage?