ok, I figure if I have an 8 foot width, I should have some extra slack on the ribbon cords. So I figure I should cut each to 10 feet.

Why make everyone the same length? Easy, time to travel then for each cord will be the same. Only way I can assure everyone LED will blow their colorful load at the exact same time.

So I have 500 feet of ribbon. Each ribbon cord has 4 sub cords built into it. So in actuality, I have 2000 feet of ribbon. Since I have 10 feet lengths, that gives me 200 ribbons. I'm totally under my required amount. I'm short 250 (I'm only doing 7 modules) plus if I want to do a mini-project I still need more. I figure I'm going to need to just buy at least another 7. I might as well just end up buying 10 for the "just in case" factor. Plus I need to buy some male power connectors anyways since I got a bit aggressive soldering a couple.