450+ isn't weak. It's approximately 155# test per strand (static load). The fraying is the tiny strands that compose the string breaking down, which will happen much faster with a low strand count (reduced durability).
Performance gains are usually 2-3 fps at best. To me, that's minimal. Almost anyone shooting can gain a lot more than that simply by working on their release.
http://www.safarituff.com/trophies.html (bottom of the page)
Never broken a string myself, but I have talked to a few that have. Never fallen from a tree stand, but I still won't get in a stand without a safety harness.
Strings don't weigh a lot to begin with. 16 strands isn't typical for dacron--I rarely build one with more than 12 -14 strands. Even with a string that weighs half, buiding up the serving/double serving/etc. is done to the most crucial point on the string.
"when someone wants me to build them a low-stretch string, I use 10-14 strands, simply so their know-it-all friends won't comment and instill doubt."
I sure don't claim to know it all, but I have been studying strings and string materials for over 20 years. I've been very fortunate to have access to BCY's vast resources, along with some of the best shooters and coaches alive. Of course I have my opinions as well, but I try to make a point to keep those seperate from fact.
If 8-10 strands of a material was a big improvement, seems to me that there would be archers who shoot accurately for a living using them. I've never met one that does in 20+ years of 3D or the last 5 years attending big tournaments like Vegas. Not arguing what a person's personal preferance is, just making a point.
I've made lots of strings for Border bows. It's only been recently he's started recommending 100% Dyneema materials like 8190 (Dyanflight '97, Mercury, etc.). I'll just say they are the exception, and in dicussions with him about string materials, he has a bit to learn yet. 8190 is a very good material, but I like 18-20 strands myself.
Sid is going to have to figure out something else, because 8190 isn't going to be produced anymore once supplies of SK90 Dyneema run out, probably around the end of the year.