I'm afraid you're putting the cart about half a mile in front of the horse here.
Speaker design goes as follows:
- Decide a goal, covering form-factor, low-frequency response, output, etc
- Carefully select drivers that will allow those goals to be met - requiring simulations for low-frequency response
- Construct the cabinet, accounting for diffraction, internal reflections, etc.
- Measure the drivers in the cabinet
- Design and build a crossover that integrates the drivers properly. NB - what works for one set of drivers will be at best sub-optimal (and at worst result in immediate and catastrophic failure) for another set of drivers.
By starting with a finished (presumably generic) crossover, you're effectively saying "I have some engine oil! Which car should I buy?"