One of the big problems with the dome was cooling it without roof vents.
Why didn't you make a vent? Fitting one or more of the triangles with a triangle-frame on hinges (with a latch stick) would let the heat chimney right out.
I didn’t put in a roof vent because I couldn’t figure out a way to seal it from the rain and wind. I made the outer benches using 3/8 X 4” Redwood bender boards in layers and then put slats for a surface. The center bench was a old 5’ redwood hot tub cover on a metal frame I had a muffler shop build. They made it in 2 parts so I could get it through the door and I bolted it together inside the GH...