Installing Two Shock Sensors

Two questions actually: I am thinking about installing two shock sensors on my 66 Chevy truck. Not sure if it is overkill or would cause problems. I would like to install one in the rear to protect the rear of the bed, specifically the tailgate. And, install another in the cab as usual. The alarm is a a Viper 5706V. It has two sensor ports so it seems logical you could connect two of any type of sensor. The installation guides I have do not address using these ports other than showing the ports in a diagram. Am I good to go by installing a shock sensor in each port? (Assuming it's a good idea to begin with).

Should work fine. Will the tailgate sensor just detect that it has been lowered? If so, a tilt switch would work as well.

I installed two shock sensors on my Frontier, one in the tailgate and another in the dash. I had the trigger wire of the tailgate shock sensor go to the "trunk pinswitch port".