Yep, cut off 2.5mm of rubber. Mentioned this earlier. You are on track. Just run a razor blade around it up 2.5mm. I would try that.![]()
They also might get away with shaving some of the rubber off the bottom of the connector.
Not optimal, but doable. It can be done in a pinch, as long as the metal part is smaller than or the same size as the ID of the antenna female socket.