Skip the M and L versions now available is a new approach. Prior to January, the model was simply a M / L. The M/L version was to fit 20 to 22 inch torsos. I guess that makes it a large. The new model is actually the Small in the line up. I would be glad to measure anything for you. The measurement from the bottom of the pack (bottom of belt) to the top centre is 22".
(I am a 19.5 torso size and it is neither too short, nor too long - i.e. there is wrap to the shoulder straps)