Yeah that's the way I'm doing it.
Although, up to you guys if you make this a league game or not. Personally I'd like to know before I wrote my list whether I was playing home or away (the defending army get's acute senses, so I may include an outflanking unit or two that I might not normally bother with) whilst the attacker gets to pick the mission, so can perhaps choose an army list that suits his mission objectives... but hell, if people want to just roll off when they get here, I've got no problem with that.