John writes:

How much does it pitch to the side if you don't put offsetting weight into
the passenger seat and how does it compare to the normal variation caused by
fuel burn from a single side at a time?

I never burn fuel from a single side at a time, so I cannot comment on that.
Both the Bonanza and the Baron let you draw fuel from both tanks, and that's
how I leave it set.

If you are heavy and alone in the plane, it has a distinct tendency to bank
towards the heavy side. The Bonanza does this, anyway, so it's harder to
notice, but the Baron will do it, only not as obviously. When I first started
flying these aircraft I noticed odd banking tendencies and it took a while for
it to dawn on me that the aircraft was simply loaded unevenly.

If you do the math I think you will
see that the moment caused by the fuel burn changes is much higher then the
moment caused by the weight of the passengers so close to the centerline.

No doubt, but I don't alternate tanks.