Great results.

Looking at these (ref) cards there is some room for simple improvement:

IMG_4399.JPG

There are 3 unoccupied spots for caps. Installing these capacitors (470uf 2.5v tantalum low esr) would reduce the voltage drop from the VRM section to the core.
It would also stiffen the voltage so it would droop less under a heavy scene. This should lead to better overclocking, and stability.