Definetely the dimple down. The dimple up looks like it was put on wrong for some reason. That's my opinion. Also, I know these are going to be painted bright pink, but why does the weld on the "dimple down" pic look like crap? It looks like the metal was bent or warped or something towards the back. Just kidding about the pink, groany groan groan, but seriously, that specific pic looks like the weld or the metal one (the piece with the dimples) didn't come out right.
"Pain is temporary. It may last a minute, or an hour, or a day, or a year, but eventually it will subside and something else will take its place. If you quit, however, it lasts forever." -Lance Armstrong.