Got some outdoor M3s installed this weekend.
These ones are set up about 13’ apart in 2 seperate pairs. The pairs seperated by 15’ or so. Each pair has a volume switch ahead of it and can be turned on/off from inside patio door. These are zoned in mono and share 1ch of a 6ch amplifier.
When 4 switched on and full volume they act as a single huge speaker 150’ away. Pleasant and clear sound by the shore. With this spacing, sound is incredibly consistent across the patio and not much louder than out in the yard. Very comfortable. Treble is a little rolled off when near the speakers (way below axis) but still highly enjoyable and a justifiable tradeoff for sure.
Since you are only ever close to 1 speaker, you dont get the cumulative effect as in the yard, so levels are even. Very very cool outcome and versatile setup. If you are out in the country and out of earshot (500’ or so of other homes) highly recommend this type of setup. It rocks! | 
