Pics are coming soon. So far, I'm going with the 12-30 cassette that came with the bike. Certainly *way* more than adequate for the test ride and, so far, working well with my home roads. Still need to explore that more.

It does look quick standing still and, my, how it just glides on the road! Wish I could tell you more about the DI2 but mine is just the old mechanical Ultegra 6700 I know and love.