I built a prototype using the Eminence APT80. It was pretty good, but I liked the sound of the Vifa better. When using the APT80, I liked it best crossed over at 2.5kHz, second-order on both woofer and tweeter, Zobel on woofer, 6Ω series resistance followed by 4Ω shunt resistance on the tweeter. Swap the polarity of the tweeter. You might give that a try and see how you like it.You can try the first-order arrangement if you want, maybe compare how it sounds with the second-order setup. When I run first-order crossovers, I like to refrain from putting a Zobel on the woofer, which makes it not truly a first-order filter. Sometimes a little more inductance is better, especially if crossover happens near a region of rising response from breakup or collapsing DI.
For a first-order crossover, I find that 0.5mH works nicely on the Alpha 8 and Alpha 10. Some prefer a little more coil, maybe 0.7mH or even 1.0mH. The tweeter should start coming in around 2kHz and be full in by 4.0kHz. Use a 4.7uF to 6.8uF capacitor followed by the padding resistors, 6Ω series resistance followed by 4Ω shunt resistance. Same polarity on the woofer and tweeter, of course.