Having just looked through the rulebook, cancel what I said above.
Do NOT use OW. Use DH.
OW is a great game, but the rulebook is a complete wreck of contradictory copy-pastes from other sources and is basically unplayable in as-written form. I can't believe they published this. It's unbelievable really. No quality control whatsoever, none.
Don't even bother buying the book unless you already have DH.
In fact, treat it as a supplement for DH.