I'll throw another size in, we just purchased a 5/16" main sheet. Use a line designed specifically for main sheets. Some of the low stretch (stiff) lines will not wrap around a smaller diameter block as easily as a softer version. In other words it is too stiff to properly grip the blocks. I think you'll find the advantage of easier use in reducing diameter only. Be very careful (or ask an expert/retailer) before purchasing a "high tech" line.

Sorry for no "specific" answer, there are a lot of different brands and "families" available.