You don't have to have 3 HQs. You don't
have to have any HQs or strats at all (for a non-MA terrain) if you don't want to. If your terrain is supposed to be 2-sided, build it that way. Then, when your terrain is built, simply load it offline and change any rook fields to bishop or knight then hit save. This gives you that field setup as a .fld file in your AHTERR folder. Just send that .fld file along with the .res file when you put out terrains and it will be preset for players as 2-sided when they go to fly on it.