Welcome and sorry to hear about
a small portion of capsule was missing
Sounds like the surgeon left a chunk inside. UCLA has some of the best state-of-the-art imaging equipment in the area, including mpMRI and C11 Acetate PET. May I suggest you talk to Dr. Kapulien or Dr. King - both have a lot of experience dealing with salvage radiation.
Key questions are (1) whether or not to treat the pelvic lymph nodes in addition to the prostate bed and the chunk left behind. That will probably depend on whether there seem to be infected lymph nodes and on your nomogram results.And (2) whether neoadjuvant ADT will improve your outcome. My layman's guess is probably not with a pGS3+4.