I agree with Dave's response to the initial photo, but hadn't considered Lex's point about maximising frontage. That's a good one.
As for the last photo, where we see the Stand and Shoot results, I'd recommend taking away the stand of Chaos Knights touching the second cannon unit. It's unlikely to make a big difference, but it does reduce the Dwarf's close combat attacks slightly (though obviously can't 'undo' the stand and shoot damage).