Personally do not recommend a kickstand on a tandem.
I don't even believe in kickstands on singles. Seems your standard kickstand protects the side of the bike that needs the least protection. If you manage bump your bike enough to knock it off the kickstand, it's guaranteed to land on the deraileur, using a standard kickstand. You buy this device to protect, what, the finish on your bike, and the first thing it does is clamp harshly to your bike on a painted surface?
The only kickstand I have ever used that I liked was a fully loaded B.O.B. trailer. Not sure how well that would work with a tandem though.