Looks great! Fairly similar to my Caselabs build that I'll be doing a build log on soon (even thought it's already almost done, I've been documenting it). I have a white S5 (no pedestal) with Maximus VI Gene, 4770k (also can only get about 4.4 and remain stable), GTX 780, white BP fittings and acrylic tubing, Samsung 840 Pro and 2TB Seagate HDD, etc. Lots of differences as well, but lots of similarities.
I'm using a 240 thin ST30 in front (push pull with Noiseblocker eLoops) and a 280 ST30 in the roof (also push pull with Phanteks PH-F140SP'S) and I'm getting about the same exact temps I got when I was running this setup in a full tower with thick 420 and 280 rads. My temps are pretty close to yours. I can only get my 4770k to around 4.4 and have it remain stable. Never gone above 69 C even under full stress but it's somehow limited by stability, not temps. I love this case and the temps I get in it even with smaller thin rads. Can't wait to see more of yours!