Unless they work for Foma Bohemia, I am not interested in anyone's theories on Foma's AHU. Fomapan themselves provided instructions to take the extra steps to dissolve the AHU for this defective batch. I have the film right here, always had. I need no help from Internet strangers seeing anti-halation layer. I've been shooting 3 rolls a week of it for months. Why the hell would I care what AFGX, or R Gould, or anyone else here thinks about this as I already have Fomapan instructions to deal with the issue?
As I have zero interest in anyone's opinion on Fomapan AHU, I did not make it the topic of this thread. Save your lectures for your kids, and focus on the question on the whiteboard: "highest safe water temperature for B&W film".
Well, in that case let me just say this: you post a question then you come back stomping like a sour grape. I don't mean to get personal, which you seem to be getting with all those who question your way of dealing with a defective batch (although didn't you say you have no packaging so you don't really know it is the one Foma admitted to bastardize in production, so only the symptoms appear same as other confirmed cases?).
Everyone does things differently. Shooting bad emulsion without stopping and trying to do what , apparently , Foma did NOT tell you to do, which is "see how hot I can process it" is something that you have made a choice off.
So complain and indeed lecture others of how upset you have become over some comments is not likely the way to respond. I think the thread had signs of getting somewhat contentious from the get go, as most do that deal with "unorthodox" deeds. i just wondered from the beginning why ask the question to start with? There was no straight answer coming no matter what. And to me your film should have been replaced by Freestyle at no charge and with apologies, if they are not out to get people that is.
Responding specifically to your question: you need to test a piece of film with higher and higher temperature until physical damage occurs, then dial back. Since some of potential negative effect may not be showing for a long time, here is where I lose logic behind this whole process.
If Foma cannot tell you how hot you can go, the only sensible approach is to use max temperature Foma actually supports, and of all sources, Foma is the only one to know that. The rest of feedback is simply an anecdotal advice that may not be even applicable to your situation at all.
But in the end good luck trying. It's clear you want to make things better with what you have and it's fine.