Thanks
@vickster
I broke mine more than 40 years ago, and it's only got worse. Here is me in my "comfortable" riding position, with both arms "straight". Oh, yeah, and that's is also my attempt at a smile
I say comfortable as this was day one of London Edinburgh London, and I got through over 1100km before bailing, and that was due to exhaustion not discomfort. I was actually having trouble with my left "good" elbow at that time, because as you can see I was locking it out. Sometime on that ride I stopped doing that and neither elbow has given my trouble since**. Interestingly, I can see from my Brooks that I put considerably more weight on my left side than my right.
OK, so that's not much help to you, but at least you can see that being comfortable is possible. Vickster's suggestion is good. I wouldn't bother with a standard fit, as I doubt their formulas would take into account our weird bones. You need to find someone who has dealt with the compromises that knitting bones can give. I've never bothered with a fit because I've always been ok, and my instinct says "if it ain't broke ..." The fact that your discomfort sets in reasonably fast means that you should be able to detect an improvement pretty quickly.
**I have broken my right clavicle since then