Apologies in advance if I resend you anything.
I looked further into ADT vs ADT with radiation and found a few recent studies. However, the vexing thing about dealing with these treatments is that there is no massive Framingham-like study to hang your hat on. At the end of the day its up to the patient and the doctor he trusts most to make the call.
From these brief notes its seem like there is bias toward ADT+radiation for more aggressive cancers with positive nodes. I don't see any correlation with PSA levels but I assume that they are framed against the usual reference for recurrence 0.2 - 0.4. The bias is probably toward the lower end with a Gleason 9.
http://www.ncbi.nlm.nih.gov/pubmed/25957435
http://www.ncbi.nlm.nih.gov/pubmed/25683831
This one talks about targeted radiation of the nodes themselves using sBRT and is goes into the work done at Mayo using Choline C11 imaging.
https://prostatecancerinfolink.net/2015/03/18/salvage-treatment-of-recurrent-lymph-node-positive-prostate-cancer-in-the-modern-era/
Don't be put off by the survival rate palaver.

Have you asked a doctor about how intense the radiation would be for salvage w/ADT? The lower the cumulative dose, the less chance of downstream effects on the bladder/colon. If you do get radiation, don't take any anti-oxidants prior to or during treatment per my radiation oncologist and things I have read to support it as it will dampen the clinical effect on the cancer.

This is a huge topic and please don't interpret what I send as any kind of conclusion. I'm just trying to supplement your analysis.

I had a lot of stuff jump out when I searched on 'salvage radiation prostate cancer with positive lymph nodes'.

The risk of bladder and other tissue complications down the road is there and, like all things to do with this, it has to be weighed accordingly. Bottom line always come back to the skill of the clinicians doing the treatment as the biggest mitigating factor.

Personally, after looking at what's being done in a lot of places, I would go to Mayo Rochester, and not because this is a Mayo site. There are a number of clinics that are purported to be leading edge, and I'm sure are, but Rochester seems to have the edge. I can't quantify that precisely. Its just what I get from gleaning a lot of stuff.