The best possible sheeting line I have ever seen just came on the market last year from New England. Is is called Salsa and comes in 1/4" 5/16" and 3/8" and in two colors, red and green.

This is the best sheet I have ever used.., it does not absorb water, easy on the hands, goes through blocks very well, does not stretch, does not kink or knot while laying on the deck.
It does not have a core, yet doesn't stretch. Check it out.
http://store.catsailor.com/tek9.asp?pg=products&specific=jnqmmmgqg8
http://store.catsailor.com/tek9.asp?pg=products&specific=jnqmmqmml0
http://store.catsailor.com/tek9.asp?pg=products&specific=jnqmnonpe0
And the price is very reasonable.
Hard to beat this stuff.

And with the modern blocks (i.e., Harkens Ratchamatic -- http://store.catsailor.com/tek9.asp?pg=products&specific=jrrqroqrq, or standard Harken at http://store.catsailor.com/tek9.asp?pg=products&specific=jrrrfoipc) 3/8" is way to big -- 3/8" is what we used to use before lines got easier on the hands and blocks got better. I would recommend 5/16" Salsa. Personally, I use 1/4" on my Wave, My Taipan 4.9 and if ever find my lost Taipan 5.7, I will use 1/4" on that as well.

Rick