Layering and shipping large vinyl graphics

[The Flaming Eyeball 4]

I'm looking at making some layered graphics with several colors. One color would be the big base for all others. None of them will overlap except to the base, so only 2 layers even with the multiple colors, see attached to make sense of what I'm talking about. These will be somewhere in the neighborhood of 36 inches long by about 13.5 or so.

Question concerns shipping. I have to roll them up to send them. Do I roll vinyl in or out for best results? I'm thinking outside as that is how the vinyl comes in the first place. My concern is for the vinyl separating during shipping if left in a warm mail van too long....using Oracal 651, and now using paper transfer tape. ;-)