I think that I might have a solution to the problem of not being able to see the green LED in higher ambient light- Create a mini-backdrop for the LED. Color the back half of the top LED black to reduce the effects of ambient light. I haven't tried it in the water yet but I did try it before and after coloring by shining a pretty strong white LED light on it in while in HUD test mode and the green was much easier to see after adding the black. See attached pic.
And if it doesn't work- never mind!
Parker