If you're running programmable servos simply hook them to a Y harness, you'll have to reverse one and then you can verify with the end points and a throw meter that you have them matched up.

Vibration dampening is a tricky thing, the sensor has to stay put, if it moves around that is bad, but if the mount is so stiff that it transmits vibration, that will be bad too.

I'd go with two layers of 3m 77 outdoor mounting tape, a plywood or aluminum plate, and two more layers of tape.