Hi Jim, As a contractor in Hawaii, I dealt with solar build-up frequently. Given your large area of glass, I would first focus efforts on having a metallic film applied to the glass to reflect as much of the sun's rays as possible. Many films are nearly invisible, like the low-e film on many windows today, and thus you would not lose any visibility. This would be your single most improvement. Next, make sure the roof system is ventilated with adequate soffitt vents down below and either ridge, gable, static, or powered rooftop vents to circulate air above the ceiling and reduce the temperature of the roof. If a fan is necessary, a louvered through-the-wall type placed high on the wall will help exhaust heat that still accumulates near the ceiling. I recommend this type because it will not penetrate the roof and will be protected by the overhang from water infiltration. Pay attention to "sone ratings", which are a measure of a fan's noise, and choose one with as low a rating as possible. Good Luck.