Hi. Since we will be traveling around the world after the tour, we have to pack for more than the tour. I know Tauck recommends for the tour carry-on maximum 15 lbs and 20x15x10 inches. From recent prior experience on this tour, what's the reality of overhead space. Will a standard US 22 inch roller board carry-on fit? Will a medium sized gym type backpack fit under the seat? What's the tightest configuration - the Dash 8 or other prop plane equipment in NZ? Many thanks!