You are correct ... at least <g> Eleanor Burns recommends cutting the length down, and others have recommended the same thing for just that bowing issue.
Personally, I have found that if I am working with fat quarters, it doesn't seem to be an issue, so I suppose I have proved it ... but, if I cut the width of the fat quarter, versus length, the bowing is even less ...
apparently, those who have recommended that we cut parallel to the selvedge know a bit about what they are talking about.
I resisted cutting the lengths of the full s to s strips down for many years, but looking back, it has never worked out well, UNLESS ... you sew from one end at the first set and the opposite end on the next strip ... well, yeah... as though I can remember which end is which! LOL too much to think about ...
and, another advantage of cutting down the length is that you can make your strips sets even scrappier ...
I am glad that you are planning on how to overcome the setbacks, shortcomings ... evidence of an engineer.