i would NOT do tinted windows, but the UV coating to help reflect some of the sun helps a lot... as you have said, when you need privacy, pull the curtains. no matter how much privacy someone thinks the dark windows give, curtains give more. the tinted glass doesnt give any privacy when you want it most, such as at night when you are tied to the dock with a light on inside...
and on the gloomy days, is nice to have as much light coming into the boat as you can get....
yes, the dow 795 is good stuff...
plexiglass (acrylic) is good. it is naturally more scratch resistant than lexan (polycarbonate).... but still get it with the scuff resistant finish on it, because you want it to last many years without having scratches in it.
I would go with no less than 1/4"... 3/8" is better but you may be limited on how thick of glass the frames will hold.... thicker is stronger but more expensive.
and you can find either acrylic or poly carbonate with different brand/trade names at a much cheaper cost, that the ones listed above.