Thanks for clarifying the earlier post and showing the spacers being talked about. Luckily my custom 'Performance Spare' brand rim is already very close to the proper offset and would only need a "shim" style 3MM shim (5MM the most) to clear even the 6 piston calipers. You do realize the spacers/ adapters that your ordering now have the stud pressed in aluminum not steel or iron. On a temp fix like a flat tire replacement I might be ok with that, but for a long term solution like you have using the R/T rims I would not be.
@motorhead says he has been ordering the adapters for years on some of his apps and I'm sure those weren't always used gingerly so I would defer to him on this.