I noticed you had a 98 RE with a T444E. Our is a 96 and has "coach" style windows and the DT444E. Our F350 also has the 7.3 PowerStroke (same basic engine with a few differences).
Our solar will be late into the build but I'm looking at FOUR front to rear rails and then mounting panels so that there is is walkway between them for purposes of cleaning, inspection, and snow removal. Want to have that walkway on the rails as well and that way have a complete shade cover over the roof and thus a barrier against solar heating.
You can follow our build at HamSkoolie.com and HamSkoolie (channel) on YouTube.
I am curious about your hatch as that's something I haven't been able to solve other than to buy an expensive boat hatch. Yours looks like a boat hatch but doesn't and I'm wondering what you did?
I have been working on coming up with floor plans on my 2000 Amtran RE. I found out the floors sheet metal is galvanized so Rustoleum will peal off in sheets. I called Rustoleum and they told me to use a Zinger product called Bulls eye 1-2-3 primer on galvanized metal. It has worked out well.