I would make it a 2H Weapon Group style (basic group style for 2h weapons) be everyman. Most likely, you could end up with several, based upon what weapons are in the 2H category in RMSS, and what weapon groups they fall into in the Combat Styles.
One of the nice things about the Combat Styles is that the individual weapon skills can be replicated easily, and so can skills for an entire group of weapons.