Daft question time again.

I've got some ceramic filters in some radios that are too wide.

First:
I've got a repeater with a 455khz IF filter that's the 3 pin type, marked
"55F" and "CM". It's in a FX5000 reciever.

Second:
I've got some mobiles with the larger filters, marked LT455FW.


I want to put these all onto a nice and tight filter. The problem is that
I'm trying to use 145.625, but there's two repeaters on 145.6125 and
145.6375 locally, so a frequency shift won't do anything. Deviation is
2.5khz peak

1: What sort of bandwidth do people recommend? I have been told that 9khz
would work a treat, but I don't know if I should go narrower or wider?

2: I've found this site: http://www.euroquartz.co.uk/ceramic-filt.htm

What are all the filter types, what do they mean (like the LTW33, LTS, etc,
etc), and which models would be suitable substitutes?


Look forward to people's responses, because this is confusing me now!


Sam
M1FJB