The -9 had its MTOW increased at the time of the QF
order, with that the wing span was increased this 6 feet. B has indicated that the -10 is anticipated to have the same wing span and MTOW as the -9. This will mean the -10 will have a reduced range by about 1,000 nm compared to the -9. But it also means it will have a wicked CASM.
I think the -10 is almost a sure thing as it uses the same engines, wings, gear, etc as the -9. It would be nice to see a future HGW version but the -10 as discussed I would expect to be a big hit with the current oil prices.