Right now, we have seen that the G10 Bracket will work with the 780ti card.
If you are asking if using a 240/280 over a 120/140 rad, which one is better? I would say the more space you have in your case for a Rad to fit into it then I would get the bigger unit. It will allow you to have more clearance for overclocking the card and getting rid of heat off the GPU.
NZXT-Eric