For me personally, the LH shot Coburn fits better since we have Schultz and Petry, but I think Boychuk is the better player.
I would go with Boychuk and hope one of them can play the left side.
I know both play the right side even though Coburn is a LS. Don't see how there would be a problem if we decided to switch him to the left side but who knows.
Even if Coburn and Boychuk prefer the right side, I don't have a problem with Schultz starting in the bottom pairing if we can get one of these guys