Top of cabinback bulkhead - above the sliding door you can see the static (at rest) gap opened up as the door-window system followed the underwing down. At sea that gap opens-closes another 15-20mm.
Foot of rail attaches to the lower omega
Head of rail attaches to the upper omega
We stopped tensioning when the inner 2mm skin cracked near the top padeye loading point
Adagio cabin back underwing sag - inside view top of door frame separation from bulkhead.
Cartoon sketch of vertical rail to fix underwing sag