Share Your Pain
I don't have an answer for you but I just thought I'd add that I am going through the same problem on a smaller scale. As you can see by my avatar I have similar issues. I am also raising my mizzen boom 12 inches for one to keep it from killing me and another to also add a bimini that is under construction now. I never had a vang but with my much smaller scale I'll be rigging some kind of multi-point attachment involving my very beefy rails for off wind work to keep the boom down.
Wickford/Narragansett Bay RI