If this is a full world tour then i think 2 dates in England would be adequete.
Not being big headed but i think after the USA, the UK would be the next most important place for Will and Jeff to play in. Maybe at venues like Manchester ENA, Nottingham Arena, or the NEC. places that hold over 10,000 but if you only sell 2 to 3,000 you still fill out the floor space.
I think they are quite capable of doing that.