Originally Posted by
roadfix
You're lucky you work in a shop so you can experiment.
My experiments over the years have resulted in a parts box full of old and new stems, mostly cheap generics to determine size, before buying the "good" stem.
I'm sure all of us regular cyclists have numerous stems in boxes. I have both 26.whatever and 31.5 oversize stuff.
One bit of advice for this guy is to eyeball stems at your shop, while not perfect it will give you a reasonable idea.
Also, take some measurements, distance from saddle or something, and height from floor, whatever works, just to have comparisons in numbers before and after.
and yes, I find in summer we tend to get more flexible and this and that, and slight changes are noticed.