All Welsh morris dances have 8 dancers and there's no reason why Wheatley dances shouldn't be danced with 8, say, Cardiff Morris Dancers (well, ever since February 1993, they have been). What's more, the only figure which has to undergo any serious adjustment is the hey.
The simple way of describing this is that the middles should be referred to as top middles and bottom middles. The bottom middles dance the hey exactly as the top middles do, but they follow the bottom pair instead of the top pair.
Having cleared this up, we really have to establish a pecking order, so as to be sure who gives way to whom when they meet. The simplest rule, and the one we settled upon, is that the order of priority at all times is:
This naturally results in the bottom middles spending most of their time dancing up and down the outside of the set while other pairs pass between them, but it works remarkably well in practise.