Somehow taking off the mast to mount a radar seems like a waste of time.
Why not put a mast/pole on the transom and mount the radar. A new pole and mounts will cost less and be easier to mount the wiring into the pedestal. Plus you wont have to pay for a 50 ft. extension cable.
And a tricolor on a mast seems redundant when the boat was wired with redgreen forward and stern white already.