I have a Birdy Classic BD-1 (unsure which mk), which comes with the fixed 10D unadjustable stem. I'm looking at purchasing a used adjustable stem, which was supposed to fit a Gen 2 Birdy. I have looked around to find any resource on the differences, and have not found much. does anyone know if a stem from gen 2 or 3 will fit a Birdy Classic BD-1?

Another question - what are the actual practical differences between a 10D vs a 25D? is there a guideline... which is suitable for taller/shorter riders?

Thanks in advance!