I will throw this question to you as well, if you don't mind.
I am looking for a 2006 Saber frame in either a 57 or 59 (but, now with the numbers you provided, I am convinced that 59 is the right size).
I found a 2007 Saber frame in 57 and it looks like the shop has a 59.
On the 57, the 2006 head tube is 167 and the 2007 is 130. That is quite a drop and likely makes the 2007 frame not work for me. But, the shop is telling me that in 2007, the Saber switched to an external headset that "added" 23 mm. So, that should make the "effective" head tube on the 2007 153. That is a difference of 14 mm.
But, looking at stack on the 57 I get this:
2006: 569
2007: 547
That is a difference of 22 mm. Therefore, it seems like the theory of the bike shop that the external headset "adds" 23 mm is false. Correct?
If there are no dogs in Heaven, then when I die I want to go where they went. - Will Rogers
Emery's Third Coast Triathlon | Tri Wisconsin Triathlon Team | Push Endurance | GLWR