[TenTec] bandpass IF filters for OmniVI - technical question

[k7gt@charter.net]

Gentlemen and ladies of the TT reflector.

I am finding I prefer listening to CW, in general, with a fairly wide IF bandpass. I have
generally listened to CW with the 1800 Hz filters in both the main and bandpass IFs, using the bandpass tuning to 'window' the filters for a somewhat narrower bandpass.
I also have the 500 Hz filter in main IF (217), and the 500 and 250 in the bandpass IF.
Recently I noticed and purchased the 1000 Hz INRAD filter for the main IF (INRAD 766) and have put in tone of my OmniVIs n place of the 1800 Hz filter. I am finding I would really prefer having the 1800, 1000, and 500 Hz filters all available, but, alas, there are only the two aux.slots (N1 and N2) at that IF. The bandpass IF, however, has three aux.slots besides the stock 2400 Hz filter. IF such were available, I would like to make the filters available there 1800, 1000, 500, and 250 Hz. (This would only be in an OmniVI devoted exclusively to CW as it would be poor on ssb) INRAD does not  make such a filter and with the passing of the OmniVI into history will likely not increase their filter selection for Tentec rigs. So.... my thought is this:

Could someone design a modification to the Tentec 285 filter (500 Hz BW at
the 6.3 MHz IF) to widen the bandpass to appx. 1000 Hz? A 285 filter is relatively
easy to pick up and the parts are through-hole and quite accessible. I could surely
do the mod but have no idea what to add or change to slightly widen the bandpass.
A strategically placed resistor? Change the capacitor values (ala Elecraft!) or what?

Perhaps there is someone on this reflector with some savvy regarding filter design
who might shed some light on such a possibility.

I am not interested in adding an external DSP unit to the OmniVI nor am I interested
in moving up to the Orion II. I am quite content with the performance of the O-VI, 
having only once ever heard any sign of front-end overload (that happened
once with the W6YL station on a ridge 3 miles away running 1500 W to a 6el
20m yagi aimed right over me!). Besides, by the time the used price of an Orion II
comes down enough for me to afford, I may be a SK or demented and deaf.

73 to all 

Allan  K7GT

SW Oregon