I like the creative ideas. I'm sure you've seen the clear engine cover made for Caymans. I installed the rear glass on my DIY Zeintop, and it wasn't very heavy at all, maybe 5 pounds. The vertical glass could work.
You might consider louvers in the side quarter glass instead. Look at the Z-art website, where there is a mock-up of that using a Zeintop.
Without hijacking your thread, I mention that I'm about to put my 986 Arctic Silver Zeintop [and the Boxster too] up for sale. I just agreed to buy a Cayman.
Offers welcome. It's in White Plains, NY. I'll do a separate topic when I have the new car.