Everyone talks about adjusting the focus on their Panorams, but what distance do you focus it at, once you have a ground glass substitute at the film plane?

Kodak says that group portraits should be at a minimum of 20 feet from the subject. Now, with a 90mm focal length, and f/11 aperture, I suppose I can use a depth of field calculator. That shows focusing at 40 feet gives focus from 18.3 feet to infinity. Is that the sort of distance folks are focusing them at?

I did a first try at focusing at 20 feet, which may or may not have been very accurate, but distant objects are NOT sharp at all.

I've used rubber coated nylon changing bag as a bellows. I may not have made it quite baggy enough, the slower shutter speed isn't very reliable about swinging all the way. Or maybe it's too stiff compared to the original chamois. Of course with ASA 100 film (as opposed to the ASA 25 film it was designed for), I'd normally be using the faster shutter speed. So I'm not super concerned.