I ran autotune again in debug. And got this
cudaminer -d gtx780ti -H 1 -l T59x4 -C 2 -i 0
This gives me what I got with the december release around 630 to 650.
Would you try 60x4 as 780ti has 15 SMX thus 15*4 = 60. Maybe it will help.
EDIT: Also should it not be t instead of T = Y kernel from nvidia.
I tried t60x4 get around 370. and T60x4 gives me 570.
So T59x4 is the best so far.