Trying to understand the best electronic crossover points for a PA stack. I use a power curve from a Beyma/Rane sheet but it doesn't go down below 250Hz. I also have the altec directivity graphs for different sized speakers. Also have access to different setups and I'm looking at how to get the most power from a particular stack, knowing all the parameters.

Any tips from the pro's would be appreciated on using 3 way electronic crossovers and choosing the best points for most power or the best points for quality at less power.