There actually is a DOT formula/regs of how the colors and lines are designed for how far back and how quickly while traveling a driver will see them and how bright they are.
I have a cargo carrier on my toad behind my MH and have been
rear ended into it twice.
.
When you stop at a light the car behind you approaches for his stop within good distance to not hit it, but then can't see the cargo carrier that is below his line of site, forgets about it and they move up and bang. Or they hit me just coming up to stop.:R
AND when I am parked at a CG or sporting event CG 10's of people have walked right into the side of the cargo carrier at night.
Once I put the red/white reflective tape all around the edge of the carrier all that nonsense stopped. :C
IMHO I would have used DOT approved White on your TT.
You should see how THAT one lights up the sky's at night "way" back "before" you come up on it. Almost blinding! DOT actually rates the reflective tape by candlepower!
We use the DOT approved white tape for just that reason all the time on the back of our horse trailers. To make SURE no one slams into the back of our precious cargo!