Drip loop. Put in a drip loop between the bulbs and ballast, and then another between the ballast and plug. I have my coralife ballast mounted to the back of my stand, but at the top of the stand(if that makes sense), so all the cords run almost down to the floor before coming back up to plug into the ballast.
However, the downside is that it can be difficult to take the hood off if the ballast is mounted to the stand. The coralife ballast easily disconnects the bulbs from the ballast, but if you go with ahsupply or any other retrokit, get a couple quick disconnects.
The other big design question in the canopy is how high above the water to put the lights (what makes this a bigger question is that it is very hard to test).
If I go with all 6 lights (480 watts / 3.2wpg), then the reflectors are 18" (3" each) wide / deep. The canopy is about 18 7/8" deep (inside measurement). If I only go with 4 lights (320 watts / 2.14wpg), then I will have a little room in the front and back.
I have to "suspend" the lights from the top of the canopy, which will be 18 1/2" tall total. I can't get the lights down too far or won't be able to open the lids for feeding, ferts, etc.
Herein lies the design question ... what to do??
Actually, it was a shelf second, but something to mount the lights to first. 4" or so off the water. Also, these are T5's, right? If so 4x80w is really going to be enough light. That being said, if it were me, I'd mount all 6, because 6 months down the road when the tank is really in full swing, you'll be able to up the lighting. 6x80 right in the beginning will give you algae to hell and back. The first 3 weeks or so, I'd probably only run 2x80 until the plants root and start to grow.
Keep it coming...
Rails and stiles for the end panels and doors (yes BK it will have doors - lol)