[TenTec] Omni VI Plus/CW/Filter Question

[Arthur Trampler]

I am thinking about getting an Omni VI Plus from my brother.  I would add the Inrad roofing filter and 9mhz narrow filters.  From what I can tell, the VI Plus is set up for a 750 hz offset, as far as the stock filters go.  Yikes, I like less than 500.  

If I understand this properly, although the VI Plus has variable offset/pitch, the 9mhz N1/N2 filter and any roofing filter have to be set for a lower offset if all is going to work.  From what I can see, my choice on the roofing filter if I want this is the Inrad 765.

With discontinuing the 28# numbers, is there a 250hz 9mhz filter, with the passband centered around 500hz?  Or the 6.3mhz if filter?

Finally, I have heard a rumor that running the lower offset requires a re-alignment of the rig.  This makes no sense to me...but what do I know?

Input is appreciated.

Thanks,
Art, KC2G