From what you saw yesterday do you think its do-able? If you do, I'm happy to pay for a premier support ticket.
Actually, I've had an epiphany. Cases where it would be useful to use AND with the checkboxes would mostly be to select some categories AND use one of the scales to filter it down. Similarly, this would be by country too.
So I think my original design of having the scales as part of the profile checkboxes was a miss-step - if I have them as separate fields in the revision table, I can use radio buttons as I now do for countries.
Meaning that on the search I can use radio buttons as criteria on the WA search for country and / or scale, along with the profile checkboxes below, where it will be fine if they just search based on OR rather than AND.