I decided to hack my own towing mirror. I used a RAM mount suction cup, "long" size arm and a
DoubleTake mirror. It works well around town, but once you hit about 60 MPH it pushes the mirror back so then both are out of adjustment.
It would probably make an acceptable water ski mirror. PM me if you are interested, since my boat already has one!
Just another data point.
Imgur: The magic of the Internet
Imgur: The magic of the Internet