You are probably right, mungo.
I wrote ~16 - ~20 mm, because I don't know exactly (I haven't tested), but ~17 - ~19 mm is probably more correct. Note "~".
C-c for D-G is a little less than 17 mm and c-c for B-E is about 18 mm (I prefer it like this), but you can go wider and narrower.
Sorry, but the SOUL V is not of interest.
Thank you anyway.