Here's the "official" 8-speed bike Sturmey was showing in their booth at Interbike in Vegas.
tcs
Yes, I think that gearing is about right for that hub, however unconventional it may look. In that earlier post, I was suggesting 32 X 24 T. Looks like I was on the right track. They may have opted for something similar, which (as I age) makes a lot of sense to me.
BTW, that's a nice bike. It is retro styled. I like how the front hub diameter complements the rear hub and even the chainwheel matches. Style-wise, that works. The front fork does not match the Schwinn frame at all but it looks like a nice fork. One final comment, if it were mine, I'd put on some fatter, slick tires (Schwalbe Kojak, or modern equivalent).