Hello Dave,
IV also started to think about what type of glasses to use. Read a lot about it. Finally took Oakley SplitShot type with mirror blue lenses.
Works perfectly on blue water but very well on green and grey water also.
In any sunlight conditions.
What I'm waiting for are the fabulous brand Costa del Mar type Tuna Alley blue mirror (glass lenses version).
Costa seems the most advanced for watersport use.
Hope it helps.
BR,
Peter