[3rdday]

Raybuds... Or pingpong ball style. The worked for me. Check the every time you go out to see that no debris is affecting thier performance, this is the biggest issue with them not working. Also you can push the ball into the silicone skirt and no water will enter.

FYI you probably already know, use 3m 5200 on the screw holes you drill to seal . you will have a real wet boat problem, called soggy transom!