Well I have the answer to my question as to the size of the piece. Wietske was kind enough to pass on the answer she received from Jo-Ann to the same question concerning the size constraints. Donna visited the museum and discussed her plans with Jo-Ann, the curator of the exhibition. She chose her spot and made the installation to fit it. The size constraint was only to ensure that all our pieces fitted into the exhibition space, which wasn’t vast. The size was not a criterion used in the judging. The judges considered the innovation, how the techniques fitted the subject, and technical execution.
So I’ve learnt something else now too. If you don’t ask, you don’t get. Talk to people!
Thanks for the information Wietske.