I would like the extra head tube on the 56
I did ride a 56cm for a little while (although a mtber, I guess 56 is my ‘road’ size), and found it just a little bit too big. But that might just be me. Headtube: there’s a fair number of stacked-up CCs, IME. I run a 100mm stem on my 54cm, and reachwise it’s fine.
Anyway, I absolutely love it – gets daily use/abuse as a commuter, pub bike, occasional rough-stuff, etc. It’s something of a tank compared to ‘proper’ CX bikes, but it’s very comfy. Can’t say I would fancy discs, tbh – it would just over-complicate things… 🙂