Having them laced into a wheel makes it slightly easier to remove the r.h. ball ring but if not I can usually remove them holding in one hand.
But yes, I do have a jig that can hold shells without damaging then. Had a few stubborn ones that required it but it's mostly used for removing l.h. ball...
Re: 4-speed Sturmey Archer servicing
Glad to be of help. It's great to see the build as it has progressed, I don't normally get to see the bikes the hubs are finally fitted to. Hope to see some more photos once it's back from the paint shop and on the road again.
Re:
Here's some photo's of your hub internals. All looks in very good condition for 60 years old. You'll see there's some slight wear on the clutch but nothing to worry about.