I need some advise on a passive crossover for the JBL 2405 and 2470 mid:

Just got a pair of JBL 2405h tweeters! They are to be setup to work with my JBL 2470 mid horns, with a passive crossover. Also, what is the appropriate baffle dimentions to mount the 2405 tweeters? Can it be mounted without a baffle?

I started playing with the crossover settings on my digital crossover DBX Driverack PA that let me try and switch between different settings quickly and easily. And I came to this conclusion:
JBL recommends a 12db/octave crossover at 7khz or higher on the 2405 tweeter, but...
I found that a 6db/octave slope sounded more seamless with the 2470 mid. In fact the steeper the slope was (12, 18, 24 db/octave) the more detached the 2405 tweeter sounded.
The 2470 mid horns roll off naturally after 8 khz. So they could be used with or without a low pass filter.

digital crossovers observations:
2470 6 db/octave at 9 Khz and 2405 6 db/octave at 9 Khz -- best sound
2470 wide open and 2405 6 db/octave at 9 Khz -- almost as good, slightly harsh on top.

JBL 2470 is 16 ohms
JBL 2405 is 8 ohms

I am interested in making a passive version. Is a series crossover an option? How do I do it?
Simple version:
What is the kind and value of tweeter capacitor for the, high pass, 6 db/octave at 9 Khz? (mid plays wide open)

Better version:
What is the kind and value of inductor for the 2470 low pass 6 db/octave at 9 Khz?
As an option, what is the network for the 2407 low pass 12 db/octave at 9 Khz?

It will be interesting to compare the passive and active crossovers, soundwise.

-Herman