I have used several of PoR 15's products. I am not as impressed as I thought I would be long term. There are many products now that might have POR 15 beat. I am currently using a urethane paint like POR 15 made by Bill Hirsch.
No problems with it so far.
There is zero rust and many others. I would try and find some reviews and see what people are using now.
I had a run of using Permatex rust treatment from Napa. It is completely worthless and delaminated allowing oxygen to waste away more metal under the coating.
I remember PC's POR 15 troubles. That was about when I started looking for other products. I was using it at the same time with out the same problems. PC is or was in a much different coastal environment. I am in the PNW with salt free air and different humidity. If a product is that particular I would find something else.
When they say don't get urethane paint on you they really mean it. You will wear it till your skin naturally sheds or you sand your skin till it's raw. It does not come off skin.
Cheers.
Liz, covid, murdered 10/19/21