Re: 69 rally wheel fitment
Personally, I would prefer a GM wheel over aftermarket.
15x7 rally wheels are plentiful. The 69 wheel (YH) is very expensive. But, the FW wheel used on Chevelles and Monte Carlo during the 70's are still around. Very close to the same off set. I sold a set of 4 a couple years ago and only got $150 for the full set.
For the 15x8, you can use a 70's Corvette rally wheel. I believe they are coded AZ. They will cost a bit more, but still around.
I don't believe any of the aftermarket rally wheels are hub centric.