Mando, 8 matched cells sounds like the best choice then, if you think the added weight want lesson any flying characteristics. Is the name brand a concern, or can I get the type that is available?
One more thing, will lmh 9t pinion fit the hacker ( shaft size) without modification?

Mossie, how many cells is this battery? By the volts it sounds like a 6cell.
And how are you getting such long flight times? I've read so much on what everyones using, that I've got to write it all down just to keep the setups straight.