to ask around in your sailing area what is the "best" paint
is good as different paints and copper contents work
differently in different regions of the world. You mentioned "winterization" so you must be "up north". Paints for the Tropics do not work well in the cold waters up north and vice versa. So ask around and get a consensus.
- - Areas where large "sheets" of bottom paint
have apparently fallen off the hull
were most likely dirty or not properly scuffed/sanded and cleaned prior to paint
application. If the rest of the bottom is okay then sand the bare spots with 80 grit paper, clean them well and then put on new bottom paint that matches what you have been using.
- - Prior to launching after a winter or any long term haul-out it is advisable to use Scotch-brite pads to scuff the whole bottom to remove any "oxidized" copper from being out of the water