I arranged what was left:
|48" x 66" - quilted on the longarm (Q-Matic "Bellflower2" design) - cotton batting|
After wrestling with it for several hours and observing the system's behaviour, it became apparent that the "realign safe area" function is where the problem is. I don't know why the system doesn't just give you an error message. Seems to me it should, but there you are.
Anyway, I managed to slug my way through.
This project did give me some headaches, but the results are lovely (I do wish my camera captured colours better...).