ghturbo2000

I have some Autometer Phantom Oil Pressure/Temp Gauges with all the relevant Adaptors and Extension Hose from Le Mans Motorsport. My question is how do I know how far to screw the sender units into the adaptors.

Because I have read a lot of posts on this website and it's a fine line between too much and not enough. I have tried to connect them outside of the car before I do this for real and with both the Oil Pressure/Temp senders the threads do not go completely in the adaptors. Is this normal?

Thanks in advance
ghturbo2000