Years ago I used to tour and randonneur with half step gearing plus granny. That was sweet. Off the top of my head, the spacing was 4-5%.
I can see the advantage of quick shifting with the Rohoff. That is why I like my electronic shifting. I doubt I will ever buy anything but electronic shifting if I buy another group. 12 speed 11-39 Rotor Cassette something like a 52/36 on the front would be my dream. I can't see needing or wanting a 10 cog.