Fast,
Welcome to the forum. As I am sure you've seen, you are amoungst some folks who could care less for going fast and some, I suppose, like yourself, are real hot rodders. That's what makes it interesting. I'm probabaly more the former, but do like to scoot it when the road is open ahead. To your question, your chainwheel ("clutch basket") would most likely have had 42 teeth. Engine cush sprokets are available anywhere from 16T to 24T (maybe even more options than I know about). It seems most folks use 22T or 23T for reasonable cruising. Of course, also depends on gearbox inards and drive and rear-wheel sprockets.
Looking forward to some pictures of your bike.
Ricahrd L.