Don't shorten it, simply grind off some of the metal from the stands 'stop' lug, this allows the stand to swing out further thus increasing the lean angle. Go slowly as it's easy to remove too much.
The other problem with this method is it can be difficult at times to deploy the kickstand. If the bike is fully loaded or if there is any rise on the ground the kickstand can hit it in the downstroke.
If the kickstand is shortened, it can be lengthened by adding a taller foot if necessary.