Good choice on the Pro LRT, great tubing and has the best bend radius out of pretty much all others.
I use the home depot clamps.. at least on some of my connections. They are a bit big and kind of take off from the slick look, but you can you use them if you want. I just use zip ties.
Loop order doesn't matter at all really, unless you have really low flow(which you shouldn't have to worry about). Just hook everything up so you get the cleanest tubing lines.
Everything else looks good, assuming you are still going with these parts:
Rad: swiftech 320
XSPC Acrylic Reservoir for Laing DDC
GPU block: MCW60-R2 (X2)
CPU block: Danger Den MC-TDX (have it already already)