I played everything offered in school: football, basketball, baseball and track. We didn't have soccer, rugby or swimming but I continued with track in college and was the most comfortable in those locker room situations. Like you said, I think it's because it's less of a team activity so everyone's shower time can be more staggered. The most intimidating locker room situation was baseball, followed by basketball. Football was mostly comfortable for me. Maybe there's something about guys being rowdier in the spring and about to be on summer break. But to answer the original prompt of this thread, that's how I would rank the relative "size" of the participants of each sport too, baseball down to football. Just my personal experience, doubt there's any science behind it, but interested to read other posts in this thread. Also, coaches showering with us was rare but happened. Never in college but more when I was younger, think this has to do with coaching and teaching schedules.