[bxyhxyh]

Originally Posted by MysteryX

I found B=0, C=.75 to give similar and slightly better result than B=-.6, C=0

This goes exactly as described in the documentation
http://avisynth.nl/index.php/Resize

Then Lanczos would be better as it written in this page. Eventually we end up choosing Spline36Resize back lol.

Joke aside, I found what I asked.

A=-0.6 gives the most consistent results mathematically, but the other modes may produce more visually pleasing results.

It says a=-0.6 not b=-0.6.
Isn't a=-0.6 is just b=0, c=0.6?

For b=-1, c=0, it changed the shape of the certain objects. So it was no option for me.

Then As Didee recommended I tried b+2c=0 values for downscales.
b=-0.6, c=0.3 had too much ring for me.
So I ended up choosing b=-0.52, c=0.26. Looked nice to me.
It was sharper than Spline36Resize and had less ring than b=-0.6, c=0.3 of course.
(Why 0.52 over 0.5? Well, no real reason at all.)