I just fit a client on a Giant Avail 1. The published seat tube angle for the small is 74°. However it is not from the center of the BB. It’s about 1cm forward of center. With a Brooks saddle and a 2.5cm setback on the post all I could get was 74.4°. .4 above the posted 74°! Her chosen angle from a fit session was 70.1° Be aware.