That little hornbeam rocks! Your gonna have me scouting for some this week. Very inspirational.
Hornbeam are an exceptional bonsai subject, you must definitely have a few in your collection.
This one by Will baddely, with similar material, a pretty boring straight trunk but two substantial low branches to cut back to.
Just look for trees with low branches, makes it all the more enjoyable and drastically shortens the time before you have something nice to look at.
For the UK members, I bought the tree from Dobbie's. Dobbies Garden Centres
https://www.dobbies.com/