Take your time doing the channels, they will repay you well. Should give a noticable improvement to the cooling.
Are you going to remove part of the fins so that the fined area is only a couple mm wider than the CPU? I'd make the fined area long enough to allow the later use of a Barton core if it were me though. Perhaps it's just me or the camera angle, but the finned area looks wider than needed. The extra width will reduce your water velocity & thus cooling.
But all in all, looking good man!
