Thanks for adding that info. I heard similar concerns and the problems described much like the ones you shared.
I can't explain the problems either but I do wonder if they have something to do with the sharpness of the edges where the failures seem to originate. On my mast the radius of the corners is large whereas the radius on the edge of toe rails is much smaller. The respective locations would seem to make the toe rails more prone to damage from being walked on or worst yet run under a dock or two (don't ask me how I know!).
Small radius corners are a problem with normal varnish as well and require occasional/frequent touching up to avoid water intrusion. I wonder if that type of problem might be one of the factors that leads to the Bristol problems being reported. The finish forms a pretty solid sheet and folks that have reported problems all seem to say it has lifted of in large patches once water intrusion occured. While I have not seen this on my mast, I can see how it might occur.
I did some test strips two years ago to see how much effort it is to strip the stuff and your friend is correct, it is a bear. I found a heat gun and sharp scraper to be about the only way to remove it and that was a chore even on simple test strips.
I can only report my positive experience on the mast as I have yet to have used t elsewhere on Whampoa. For all other areas to date I have used the Interlux Schooner product and find it does well here in NC. To be sure, I use it because I have used it alot, I know how to work with it and it seems to work for me. The pros here all seem to favor the Epiphanes products but I have only used it a few times, didn't care for how it worked in our heat and thus never learned to use it and love it like they do.
When I brought Whampoa to NC she had been finished in Port Townsend, WA using Epiphanes over clear epoxy. I found that finish combo didn't hold up here in NC and in the end, wooded t all off and went with the Schooner. That was also a bear to remove as the epoxy was a pain.
Good luck with your project.
Sorry I don't know the right answer for your application.