How long should a motorcoach group allow for this visit?
Yes definitely call then if you'll be having a large group attending. From what I remember there had only been one or two guides there. But they may be able to make accommodations for a large group.
I agree -- calling them is best. The length of the tour and what is possible to see and hear will depend on the number in your group. With advance notice they may be able to get an extra guide or two in to accommodate you. Great choice!
I suspect that with advance notice, the museum could organize the tour to accommodate everyone. Because of the (delightful!) demonstrations, I would estimate at least 90 minutes to 2 hours. By all means, call them.
It is a guided tour and there is a lot to see and hear, couple hours at least. I think you should call them directly.
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