I think I'd choose which side of dividers based on what people are going to crash into. If the outside is easier/safer to bale up, then go there. Same with the inside. It might make sense to change it up on different sides of your rectangle. I'd also consider manhole cover placement

A course (direction, street names, and Google Maps link) would be good for a quick look-see at the specifics of each corner.

Leave wide parts wide, IMO. Cones are more likely to be involved in a crash than curbs for some dumb reason.