Big bolt vs Small bolt

I'll add a few snippets:

Many cars thru the 1960's (even Japanese) had LH thread wheel studs on the left side. You can find charts on the web. Somebody proved they were less-likely to loosen, but that proved too complex for people.

SBP is identical to today's 5x100 mm bolt pattern (for practical purposes), but that doesn't help since all cars with that pattern are FWD and those wheels don't work (wrong "back-space" for our cars).

The OP should insure that his 8-3/4 rear has the correct width. I am guessing he has an early A (always tell us), which were narrower than 1967+ cars.

Spoke wheels might be an option for SBP. My 1964 Valiant came with them. I don't know the vintage, but "made in China" so probably fairly current. The adapter has 3 bolt patterns, one of which is 5x4"D and fits my car, and is "lug-centric" (i.e. centers via the nuts, not a "hub register" hole). The main problem is that one must use an open-ended wrench on the nuts (perhaps a real thin socket would work, say Snap-On?). Interestingly, the center spinner nut which secures the wheel is LH thread on the right side (they are labelled). Not sure why that is opposite our lug nuts, but must be a theory. I need to get a spoke wheel spare since that would make a road-side repair much simpler. Don't know if these 14" wheels will clear disk calipers.