68 barracuda lower side stripe
Wecome to Fabo!
I have done both, without dimensions.
Don't have a clue where you would ever find them. I just went by the pictures (on my Formula S fastback) that came with graphics on my stripes, since I didn't paint them on. I think you could do the same with painting.
As far as the cutouts go, the exhaust exits on the inside of the frame rail, on both sides. The hanger helps offset it almost to the center of the frame rail. So that is what I used to cut mine out.