I have a few millies, and I have moved the pickup selector on all of them to the upper bout, like a Les Paul -- which, in my opinion, is where God intended it to be :-). I played a Les Paul most of my life, and my hand automatically goes there, no matter what I am playing. Plus, I think it's the location that allows for the fastest pickup switching when playing.
There is a caution to be taken, however. The space below the top on the upper bout is not large, so you need to go with a 90 degree switch instead of the straight one (switchcraft makes them), and have a skilled technician do t