Not to seem too picky, but reducing the coupling caps to narrow the bandwidth is not a linear function, i don’t think.
I think you will have to “guess and adjust”, an iterative process.

Didn’t ER magazine have an article where the author did this ?

You can forget the “regenerative IF” kink ( as suggested in 73 magazine and that conversion booklet on the ARC-2. )

That is BS.

-Hue Miller