Nice paint job. I missed the fact that you are doing only your CPU right now --- that's a good idea, and something I'd definitely recommend for your first time.

What I do is mock up the tubing first ... set everything in the case, measure your tubing - even attaching it to make sure if you want. Then, I tear it down and test outside the case. With the GTZ, this is pretty simple, because you don't have to remove the motherboard to get the waterblock off (altho the HAF does have that nice cutout in the mb for those not using the GTZ. If you are worried about your rad fittings leaking, you can estimate the tubing without putting the rad in, then test with your CPU loop out of the case before re-installing everything. Hope this makes sense. Careful is never a bad thing when mixing electronics and water.