It does work, now, and as you point out, the UI is not the slickest. Are you referring to the method where you discussed popping a window via scripting and selecting from there? It makes sense, to a point, but wouldn't I have the same issue with multiple lines in a portal in a separate window? With a list layout, wouldn't you have to open that window a number of times = to the number of choices needed?
The original db had checkboxes, but the number of choices outgrew that solution, and it was impossible to keep in sync with the images db. This works, for now, as it's only me using the db.
As for validation, the combinations are often NOT unique -- one of my reasons for tracking this data is to find reocurrencs of the same combination. Are you saying that each submission record should be unique, or to validate the choices as unique? Not sure I understood the reason for unique validation.
You've been a great help -- glad I stumbled in here.