I'm a bit curious, what is the purpose of the underwater lights for you? One thing I have noticed with most that the customers are usually underwhelmed with what they see in the water. They are more decorative than anything, sort of like the under car lights, while most people seem to expect them to act as big spotlights to see lots of fish etc, or functional that they could see the bottom.
Especially if there's any pollution in the water, or boats with swim grids on the back, it doesn't look anything like the photos in the ads.
The latest ones we're using are these: OceanLED - Colours TH HD
they are a lot brighter, bronze and use a much smaller hole, with a synthetic spacer for metal hulls, power hungry though.
What about surface mounting them? If it's just for goofing around at anchor, you could put a magnet on a nice waterproof bright light and stick it over the side and have a useful tool in the meantime.