Update after visit to the dealer! Well dealer was completely confused and did nothing. They did put a penny size drop of dicor on a antenna screw and were nice enough to want to charge me $139. Note I explained extensively and left pictures on the dashboard for them.
After a "discussion" while standing on the roof they ended up just covered the crack with dicor.
So much for careful consideration of the best way to repair it!
In the end I believe this may be the best way to repair it. Replacing the whole roof seemed like a greater risk when you consider opening all the seams again. Will just need to keep any eye on it.
My guess this crack came from handling of the roof sheet during assembly.
Dealer did agree the roof and a couple other minor repairs were all warranty work and there was no charge. I appreciate that but not great service.
Ready for the next trip now !