Mary and I had a Mac36 that had the wing float at the top and did very well with it.
We won most of the races we were in. Don't think it slowed us down any.

Great part was that the boat came with a self-righting system. After the boat was on its side (unable to turtle because of the masthead float), you pulled out the huge waterbag stored on deck, used the jib sheet and spin pole, attached the spin pole to a ring installed under the tramp on the hull and the other end to the jib sheet attached to the bag.
Fill the bag with water and winch the boat upright.

At least that was what the instructions said, although we never had to use it.

Rick