Thanks, Mark, that's a good suggestion. I think push-pull will work for the bridge PU, where I prefer the series and parallel mode. However, on the neck pick-up I also like the single-coil mode, which actually sounds best when I tested this.
My main question however was, whether there is some dedicated fans of Tune basses who are keen to get such a rare Tune bass in its original form. But it doesn't seem that way, so I will probably just experiment with this one, and find my drilling machine to mount two extra switches![]()
You could always put the switches in the same place that Tune does when they install that option. Just off side of the bridge. Here's an example.