I scaled the sign to print on my bed at a diagonal, which was about 50%, then just scaled the covers to the same %. When I scale it down, I scale down the X+Y but keep the Z at 100 to make it a little thicker.

I like to start from the right and feed the LED's all the way through, then back the other way. Once they are ran, I carefully peel and stick and push as I put the strip in place(Its annoying but looks nice), and lastly I put the connector on and glue in place.

I used these lights, but make sure you get the controller with them as well