Electrical , Not cranking by key

This is a non-oem setup. 1973 scamp with RB, internal voltage regulator, no ballast resisitor and hyperspark ignition coil and distributor. The issue is that when I turn the key to start, nothing happens.

I have verified that I get 12.65 v to the yellow wire going to the starter relay when key is set to start, no volts for off and run positions.

When I jumper the starter relay, the motor turns over without issue.

This leads me to believe that either the starter relay is not working correctly, either broken or not hooked up correctly. OR that the neutral safety switch for the 727 is not working correctly.
Correct????

Can I ground the starter relay, bypassing the neutral safety switch, just to test the starter relay??? trying to eliminate one factor.. There is no driveshaft, so not a safety issue of starting in gear. This seems easy to try but I don't want to break something.

How do you test the neutral safety switch?

Am I missing something?