Hi Tom,
Congrats on your new 845 panels.
I did the same when i upgraded my U790’s.
One thing I did for my frames, and you might consider for yourself, is to have a set of extensions made by Roger’s frame fabricator so the frames now match the height of the new panels.
The extensions have a slotted inner tube that slides into the open top of the frame and neatly finishes the look. The extensions were unpainted when I received them and i had an auto body shop paint them to match the existing finish.
Attached are a few pictures along with Roger’s diagram showing their construction.