There you go--a definate "maybe".
How much you gain, if anything, depends on a ton of variables, including the bow, tuning, etc.
Ken Beck did a challenge--basically offered a free BW bow to anyone who could show a minimal speed gain (2 or 3 fps I think) by changing the string from their standard 14 strand Dynaflight '97. If you took the challenge and failed, you had to buy a BW at regular retail cost. As best I could find out, nobody took the challenge--that speaks for itself IMO. Might be some threads on that here if you look.
Quiet is a relative term, as is "skinny". I've never had to go to extremes to get a bow quiet--just takes some tuning know-how and some tinkering.
Being the in the string business, I pay a LOT of attention to who is shooting what, especially at the big tournaments like the IBO Traditional Worlds, and I watch some Olympic shooting on YouTube. I see the winning shooters with moderate, even "fat" strings--at least that's what I've noticed. The strings that Fred Bear, Ben Pearson, Howard Hill, etc. used for amazing shots and lots of dead animals were quite "fat" by today's standards.
That being said, if you are really curious, try one. I've tinkered with several different materials and strand counts, and personally haven't found any benefits to going with a tiny string/low strand count string on the bows I shoot. I do think you will gain more, performance-wise, with a lighter string on lighter draw weight bows...but I've never seen anything close to what others have gotten...maybe 2-4 fps.
A few strands of string material just doesn't weigh that much--especially after building up the serving area--and that's where any performance gain comes from.
But again, it's a reasonably cheap experiment--give it a whirl and see what your results are.
Chad