Splicing ground and 12V after bulkhead.

So my haltech 1500 has 3 20AWG Sensor ground signal that is spliced together and provide ground to all the AVIs and SPIs as well as all the shielded cables. I am passing them through a Mil Spec connector that has 14 16AWG positions and 27 20AWG positions. Needless so say I am running short of 20AWG positions so I am thinking if I join 3 20AWG sensor ground into one 16AWG position and split them after they exit the bulkhead i could save a lot of positions as well as 5V and 12V. My main concern is current draw. So here is what going to pass through the bulkhead that I plan to join the ground:

- Cam ground (12V)

- Crank ground (12V)

- Oil temp and pressure sensor (5V)

- DBW (5V)

- Air Temp

- Coolant Temp

- Knock Sensor

Shield should not be a concern cause I dont think they have a lot of current in them. Would one 16AWG position be able to handle all the ground spliced or should I split them into two?

Will I be able to get away with passing the 12V for Cam and Crank through one 16AWG and all the 5V for the sensor through one 16AWG? Is it a good idea though?

Theoritically three 20AWG handle 12A of current and one 16AWG handle 8A. Would all my sensors draw more than 8A?

A single size 20 will be fine for sensor ground. It will certainly have less than 500mA, in most cases probably less than 100mA.

Thank you Adam! That saved me a lot of headache.