Just finished rebuilding my original hatches which are solid teak
I replaced the old Plexiglas with 3/8" Makrolon polycarbonate which had a light grey tint to it but offered no UV or heat rejection properties. Previously I had tinted all the hatches and portlights
with a 3M tint but it allowed a lot of heat transfer to the interior
to the point that the A/C was working extremely hard to keep the temperature down especially in the summer down here in the Caribbean
. This time around I purchased a film from V-Cool which I had used before years ago during new construction projects. WOW I forgot how good this stuff is at rejecting heat. I applied the 70 series which is almost clear so there is no major loss of light but it rejects 77% of the heat, blocks all of the UV spectrums and keeps the interior
at least 15 or 20 degrees cooler. If anyone is looking for a great film to help reduce internal temperatures in their cabin
you need to give this stuff a try, it is very expensive but worth every penny.