command squads are 4-9 men + a character. They can also have librarians and chaplains attached to them. But only one of each character type.
So the max size would be 12.
Commander + 9 men + Chaplain + Librarian
Dark Angels 1750 win/loss Record
Win - 23 (Belial helped wreck Ryan's puny Eldar)
Loss - 13 (Brice's Necrons wiped me)
Draw - 2 (The 13th hold out in alpha take and hold)