regarding the blackish marks from the shoulder harness...I've noticed that I don't get them. I'm guessing because I'm only 5'9"...what does that have to do with anything you say??? Well, the taller guys will have the harness pulling UP and over rubbing more on the shoulders. Also, some FOs I fly with run the belts under the epulets causing direct contact of shirt and belt.
Yes...I know...that all sounded dorkeshly technical, but it's the only way I could word it.
See you in the badda bing...