oops sorry... one more thing. There is only one drawback to this set up with the Topeak Explorer and that is that the support arms come down to a point. So you are limited as to how much surface area there is on the bottom of the rack to attach the bottom portion of the Wald to. With the bottom portion unsupported, it will flex a little bit under heavy loads (even though the Wald is rigid).

I got another rack that I use with three support arms that are spread out - the rear support arm goes straight down, then curves, allowing me to have a lot of surface area for bracing the bottom of the Wald basket up to.

Scott