Plus Size Cowl

I want to make the Dew Drop Cowl - but being a plus size girl and therefore having a plus size neck I would like to make it bigger around so that it would have a bit more drape.

How many extra stitches would you suggest - I’m a size 22.
I was thinking somewhere around 20% or an additional 40 stitches.

It’s a pretty loose cowl to begin with so I’m not sure you need it larger, but it appears to just be a multiple of 2 so you increase in increments of 2.