Honestly I don't think the std whelen has any problem with headspacing. I believe the issue is it's one of the oldest wildcats and hence there were likely variances in chamber reamers as well as the skill of gunsmiths not to mention hand loaders that were setting back shoulders.
I believe this explanation to be correct and is what I read regarding potential headspacing issues.
I also agree that a 50 FPS gain is not worth the effort.
It's much easier not to set the barrel back . . . just saying . . .
