Couldn't find a diagram with my specific set-up. I modified a diagram originally drawn by BMN to show my set-up. Does this diagram look correct for my application? TIA

 

I believe this is what you're looking for. Excuse the quick MSPaint job, I can re-work it if needed in PS

With the NX TPAS and Timing Tuner... you tap what would be the Ground side of the N20/Fuel Relay in to the Gray wire on the Timing Tuner (The relay now will receive its ground through the Timing Tuner). Then you splice the White Wire from the Timing Tuner in to the Brown wire of the TPAS where it would then go on to the 12v switched side of the relay (Opposite of the post you ran to the Gray wire on the Timing Tuner)

In your diagram you have the Relay running direct off of the switch which would negate the point of having a TPAS.

Hopefully I was able to explain it properly... I'm fairly new to nitrous myself, but I've spent quite some time designing/reading up on various install designs.

 

LOL, Thanks for the reply Rich. I was in a hurry this morning and just realized after reading your post the Timing tuner wasn't even on the drawing. I'm a dumb ***. The drawing looks great. Thanks for the help!