Hey Mish, sorry about those results, but today’s treatment options turn a once lethal disease into a manageable chronic one.
You will probably be placed on ADT as you heal before undergoing salvage radiation. As you correctly point out, PSA does not supply a good basis for treatment in your case, so no matter how low your post-op PSA is, you cannot wait IMO for the magic .2 before initiating salvage treatment.
Also, be sure your RO is including the pelvic lymph nodes and not just the prostate bed - something like 35% of failed salvage rad. occurs in the nodes. Best
Phil