I have read that the wheels on some bikes don't line up anyway, so I wouldn;t worry too much about that.
Maybe even check your current set up- you may be surprised at what you find!
Some of the K bikes had a spacer between the drum and the hub, and these have been used behind the spoke wheels on GS's to push the wheel over to enable large knobbies to be fitted, without any reported detriment to the handling.