I want to watercool an X99-5930x, 2 Hydro-TitanX and an Intel 750 PCIe SSD on an X99-Micro, using Monsoon 1/2 x 5/8 hardline tubing...my problem is that there are only 5 PCI slots, and I want to use an external radiator. I was thinking of using an L-bracket with dual 1/4 fittings, but there are no more PCI slots to use.
 
There are four solutions- switch to a pair of 980Ti Kingpins (which is single slot), switch to a non-PCIe SSD, use an S8 case, or use the holes on the back of the chassis. 
 
My question is this: what is the size/diameter of the holes (the CaseLabs site does not specify), and is there a bulkhead fitting large enough I can use to stabilize my tubing at the inside/outside interface of the chassis?  An M20 bulkhead? Edit #3- I want something like the Koolance L-bracket that I can plug fittings in to on both sides (internal  - Hardline, external  - soft tubing) of the chassis, but I don't want any 'give' at all- I want it to be anchored.
 
If not, will it be a system-killer if I do not have a MB that the L-bracket can fasten in to for the S8, since I don't think I can justify the Classy or the FTW?
 
Hopefully, this makes sense.
 
Thank you so much, in advance.
 
Edit to add a fourth solution...and my tubing size...and clarification...
 
 

Grey_Beard
What size tubing are you wanting to use? I have a number of CaseLab cases. I am not home now, but can measure them to make sure you have the right size tubing.

1/2 * 5/8