450+ should be quiet, but again there are lots of variables, strand count and string build being two big ones. For my part, I've experimented off and on with different strand counts in different materials and I haven't found any real benefits to going skinny or fat in strings. I like a happy medium, as do my bows. I've been primarily a longbow and selfbow shooter the past 20+ years, but I also shoot recurves from time to time. It's been a while since I've used 450+ myself, but if I recall correctly 10 strands was my preference.
I use the size serving that gives me the proper fit. I can't tell much if any difference in the way a string feels on my fingers when I do this.
It's like bows and arrows and broadheads though--it comes down to what you personally like--there's no one (or two, or three) "right" answer(s). I've been studying strings and string materials for a good 20 years, and the more I learn the more I realize how little I know.