Just watched the video. That is a huge wheel!
I did do some measuring with a tape measure and level. Then did some calculating based on my understanding...and came up with the offset being about +17mm.
This jives with an
image I saw on kyushashoes.com that had a 17 in a column beside the 14x6 wheel. I had figured that column might be for offset even before measuring, and since my relatively imperfect measurement (backspace measuring a hair under 4 3/16" or 4.1875") calculated out to 17.4625mm, I'm guessing that is indeed what that column is for.
As for the calculation, here's what I did...let me know if I'm off base. I took the edge to edge width (not bead to bead) of 7" and subtracted 4.1875", giving me 2.8125". With the center line of 7" being 3.5" I subtracted the 2.8125 from that...giving me .6875" times 25.4 to convert to mm. Pretty sure I added some steps, as I could have just subtracted the 3.5 from the 4.1875" to find what was additional. Or maybe I'm totally wrong?
All that said, after having a chance to get a better look, I think the rubbing I heard when spinning the wheel was just the brake line beside the caliper on the inside of the wheel. It just needs a little massaging to tuck in a bit better and should be fine. I don't see anything touching anywhere when turning (well, there's a bit of scraping noise...but that's coming from the steering column on the heat shield

)
So, I was a bit rash yesterday. I think they should fit fine after all. And they even cover the hub well. The center caps fit on easily, even if the years have been rough on them. But, my 1600 is a bit rough as well.