I sent much of this info in a PM to Chutley, since I have an as-new GCX sitting here for sale, but thought I'd add it here, too, for those who might embark on this in the future ...
When I rackmounted my pedals, I had Redco build me custom cables with Mogami cable and Neutrik connectors. They are right angle on the pedal end and straight on the GCX end. I had them built like TRS cables, except instead of a TRS plug on one end, there are two 1/4 plugs on each end. This makes the overall amount of cabling much thinner than using regular cable, which is really important for the pigtail of cables that will be exiting the rack drawer. I had them made 40-inches long which was just about right for having the GCX and the pedal drawer in the same rack. Initially, I tried to make my own cables with those pedal board kits, but it became a huge headache, you're dealing with 16 cables and 32 end jacks (the kits have 10 plugs, so you'll need 4 kits, and it's a nightmare with the right-angle plugs those kits come with on the GCX end of things because the jack panel is really cramped and there are issues when it's in the rack. You'll also need more raw cable, they come with 120 inches in the kit, and you need about 640 inches total.) I finally had Redco make me the 16 cables (actually 8 pairs), and it worked like a charm. I still have an expensive tangled rats nest of do-it-yourself cabling and cable ends lurking in a drawer somewhere.
Keep in mind that you'll also need a bunch of short (6") cables to connect the loops and a couple of longer ones to go from loop 4 to loop 5 on the back of the GCX. Don't use regular velcro on your pedals; get some 3M Dual Lock, and your pedals will never move once you put them down. You can also get the same stuff at Radio Shack, under their own name. You'll also want some cable guides to route the cables on the rack drawer (make sure you get the kind of drawer you can pull out all the way), and Radio Shack has these little adhesive labels that you can write on to identify each cable and then it wraps clear tape over the label itself, that was a life-saver, too.
The whole thing was a learning experience, to say the least. I did it about four times before I was happy with it. It's a bit of a nightmare to get it working, but the difference in your tone is pretty startling. It's worth the effort, but you want to make sure you do it correctly, because if there's a problem at a gig it's going to be a big problem ... LOL
