Didn't know that about UV coolants. Thanks, then I'll just change to regular dyed coolant to prevent gunk. Also, on the tubing, I work in the Chemistry department's Stockroom, so I'll be checking later on the types of cooling. I know 1/4" is small, but don't know how small. However, but by the sound of you post it seems its best to go with either 1/2" or 5/8".
Also, in respect of the fans, care to point me in the right direction? Also, I wish to keep 2 loops, not because I don't think the radiator won't handle, it's because I want optimal performance from the CPU. So if it shares the loop, some heat from the other blocks will make the heat dissipation lesser than what I want. Also, if anything happens (like a fail in the loops) I have one working. Say the second loop with GPUs and chipset fails, cooling keeps on with the CPU and vice-versa if the opposite happen.
Any dyed coolant can come out of the fluid depending on the type of block. Generally dye is to be avoided as it will stain up your tubes and can gunk things up. There have also been isolated instances of it separating entirely and forming a hard residue(though is is VERY isolated and not highly probable).
I have found for tubes that 3/8-5/8 is the sweet spot, thicker walls allow for tighter bends and won't kink as easily.
**Fans: I was mistaken, I thought you were using the GTX rads

You can see from this chart that the medium(1800 RPM) Yate's are fine(Yate Loon D12SH-12 model, run lower using a speed controller).
Enjoy!