dbbeland,
Your statement could be misleading to some people who are just learning about Auto-rx. The Auto-rx rinse phase istructions clearly calls for a conventional oil.
For the sake of this discussion, I'll assume you were referring to a highly refined Group III oil like Amsoil's XL-7500 series when you used the word synthetic.
With that said, I have the same mindset that irollturbo has stated in his opening post. Putting a standard conventional oil like SuperTech in my vehicle is not an option I would consider in the future now that I have done an Auto-Rx rinse twice. I hated using the conventional oil so much that I was considering not using Auto-Rx in the future even though I was very happy with the results I had obtained.
Knowing about Amsoil's quality standards and trusting the company like I do, I would not have a problem with using the XL-7500 series as a rinse oil. Since I plan on driving 2000-3000 miles anyway during the rinse phase, why should I care if the XL-7500 takes a little bit longer to work than a Super Tech oil as long as it does finally do the job?
Bobby