Hi chaps

This is my first post to the forum so please be gentle with me.

Over the last several months I have been gathering components for an all-JBL horn system.The plan for each stereo channel is:

2 x 2235H woofers in approx 10 cu ft reflex boxes to cover up to 500Hz.
2440 compression driver (with 2440 or 2441 diaphragms) on DIY conical horn to cover 500Hz to 5kHz.
2404H tweet to cover 5kHz up.

I now need to concentrate on the crossovers. Any suggestions? I was thinking of the Marchand XM126 active tube crossover. This is available as a 3 way with a choice of plug-ins which set the slope and crossover frequencies. I'm a tube freak so I'd like to avoid solid state in my system (no offence to the SS crowd).

Forgive my ignorance, but would cards for a 24db slope and 500Hz and 5kHz be OK? Is there any benefit in using shallower slopes? Will the JBL drivers need any other EQ? Is there any benefit in setting up the drivers with asymmetrical slopes and/or frequencies? If so, the Marchand won't be suitable without mods.

Any suggestions welcomed. Thanks already to list members John and Ted (locals).

Many thanks. Doug (Canberra, Australia)