Muppet - when I did one of these, they sold the "window" so no moving about and they pulled the seats out on the viewing side.
@JRBT - a minute of internet sleuthing and a mail search on my computer reveals our paths crossed in Tahiti 11 years ago....
My considered opinion is that for this one flying one wing low is not advisable / practical nor feasible. Whilst I have not looked at Fred's predictions for this one, but I assume you are FL390 to get the sun's disk as high as possible. This altitude is fast approaching the limit of the flight envelops for the type (although likely you will be lightish). You don't want to be doing anything that upsets the ability of the aircraft to fly (like create more drag by flying slightly sideways). Furthermore, you can't just switch the Autopilot off and fly one wing low without ATC RVSM issues.
The best approach is to ask the charter company to contact Airbus directly via their Technical Pilot through the Airbus Tech Request channel. Airbus flight test pilots and engineers will review and advise. You don't want your charter company trying anything odd up there with you and your pax on. 2 weeks should be enough time.
Final thought - if you are going to not sell the shadowed windows, you will need the crew to fly the aircraft in heading, not track. A crosswind on a fixed track will alter the heading of the aircraft and in turn change the wingtip shadow location on the fuselage.
Good luck antumbra chasing!
Last edited by compressor stall; 25th May 2021 at 09:45.