I mounted my levers where they natural fall under my fingers. I installed the extender for my Ortlieb handlebar bag. It's very strong; I have faith that it will work, but I haven't taken it on tour yet.

Incidentally, if your old cable is looking a little frayed, don't order a new one when you order your extender. You need a longer one with the extender, and it comes as part of the package.