Likely you will use Algonquins (outdoor M3s). You may want to consider setting them up far in front of your sitting area so that you have some sense of a soundstage. I've tried M3s 12 feet apart with an MLP of 14 feet and the soundstage was excellent. You may be able to place them further apart perhaps - you'd have to experiment. You could also place them further than 14 feet but that may not give you enough slam - if you really care about that outdoors.
An M5 outdoor would require some research from Axiom. The enclosure has to be made stiff enough for the extra weight of the HP driver and the mid. And it can't flex under dynamics.
