A couple of things regarding crossovers...

1. Manufacturers and customers often confuse polarity and phase.
Phase is frequency dependent; polarity can be changed with a switch or
leads reversal.

2. The best way to set up your triamplified system with electronic
crossover would be to beg or borrow two items:

An electronic test setup, whether it be MLSSA, TEF, Smaart, et al.
This will allow you to watch the adjustment of your parameters in near
real time, visually see the true capabilities and limitations of the
enclosure/loudspeaker system and adjust your crossover accordingly.

Prior to testing, procure one of the Thiele Small loudspeaker enclosure
design packages that include the speaker parameters of the components
you own. This will quickly get you in "the right ballpark".

Good luck.