Here's mine.
I used gromments I picked up at McMaster Carr by Kennard Industries. They're really pipe grommets but they the perfect amount of stretch to them. Being they were so cheap and not knowing exactly what I would need I order an assortment of them.
Pick them out based on the tube size. I then used a step drill bit to drill the holes for them.
https://www.mcmaster.com/#pipe-seali...mmets/=15rtocw
Half of these wires went to the front and half to the back. There's a few more photos in my build thread.