I'm not a fan of skinny strings. Twelve (12) strands is as low as I'm going.
Both of my recurve bows use 12 strands of Dyna 97. However, for the serving, I'm like most people. I pay attention to nock fit.
Since I use Easton Super Nocks fitted to my aluminum arrows, my serving is made up of 62XS in size (.025). Doing it this way avoids a double serving since the diameter is perfect for my nock fit.
I don't like Halo since it isn't durable enough to suit me. It wears out quickly for me whereas 62XS doesn't.