Did a bit of digging, as it's an interesting scheme.
Last season they sold roughly 1 flexi ticket for every 3 season tickets. If it's similar this season they've actually sold about 12,300 season tickets.
The gap between the price of the flexi ticket and the price of the season ticket has reduced, so the figure may be a bit higher than that, but I'd imagine they'll come out with similar season ticket sales to us (albeit at a very different price).
Beyond that, their very high pay on the day prices will probably keep their attendances below ours, although a lot will depend upon how the two teams do.
One interesting aspect is the difference between ticket sales and actual people through the gate. No doubt they will quote ticket sales in their attendance figures, but their pricing structure means lots of people who are only going to attend a few games this season will have season tickets (apparently even people who live abroad are buying them).
Even if the attendance figures they announce are close to ours, they'll have a lot less actually in the ground.
Either way, it's an interesting experiment. The only bit I really dislike about it is the fleecing of away fans. I also think that will be bad for the atmosphere in the ground, as away followings will be significantly reduced.