Wrap your chainstays with something that's got a lot of friction, but not too thick - just enough to protect the finish. Use some loctite or equivalent. You don't need to go crazy tightening down the mounting bolt if there is a lot of friction between the plate and the stuff you wrapped your chainstays with.
I cut my ESGE's legs quite short and it has worked fine for me - even in sand. Ultimately you can just cut a bit at a time so you can see what you think until you reach a length that works for you.
Can you suggest a suitable high friction material? I already killed the paint job on the underside of the stays just attaching it loosely to see how it would fit.
I just ordered a clickstand. I'm going on tour next month and I need something to reliably stand my loaded touring bike. This pletscher stand is really, really cool, but I don't trust it to not cause me grief in the middle of nowhere. Plus my bike is already heavier than I'd like.