i'm guessing it's going to ring in right about 600 g for 3S
The dual 4000 lihv is 550grams which is very close to the limit already. That's amazing that only 50 more grams would give you 10AH. If Mavic can pull it off, that would give some serious flight time. Another option would be to do what BeanBubba did and gut a stock battery to remove the cells and add connectors for the externals. Then you'd have a fairly light setup, shedding well over 150 grams and having 10AH capacity.