Looks good, only thing I would personally change is get 16/10 primochill tube. Also get more than you need, few metres extra.
13/19 is very thick and the fittings themselves are on the large side. The tube on my build in my sig is 16/10. But its to your preference I guess.
I just used EK advanced compression fittings on mine with same size as the tube. And any angled fittings if you require them.
I'm sure EK do 780 Ti blocks as well. Don't know if you can get them from OCUK, but you can get them from scan if its a reference board