From what I understand, heads should be level when installed, this supposedly optimizes the heads for straight line shots or off axis shots. I also understand that these systems are susceptible to incline/decline shots (cresting a hill, being shot from above, etc.). I can see this being a limitation with a single head install.
My question regards a two head installation, I was wondering instead of leveling the two heads, what would happen if each heads alinement was say 5 degrees off center, meaning one head pointing up 5 degree's while the other pointing down 5 degrees. My thinking is that the protective "cone" would be increased horizontally providing more protection against the high/low shots. I'm also guessing that the head pointing up 5 degrees might experience some degradation with sun under the right conditions but should be limited. What do you think.