Pretty sure it would not work with Protos, mechs get a penalty depending on size of mech & proto. I would imagine it would work the same as the Omni answer, since magclamps are more restrictive on the carrying vehicle.
Love to see some Dragoon PA(L) or Light BA . . . rides a motorcycle or hoverbike to get to a deployment area, dismounts and proceeds as the normal BA. But operate/dismount has not been a mechanic BT included for table top, leaving it to RPGs.