M_Boats: Halyard question

I'm currently replacing the sheaves on my M-17. They were used with rope-to-wire halyards and are kind of chewed up. I'm thinking of going with all rope halyards (Sta Set). Jerry recommended 1/4" for the main and 5/16" for the jib. The sheaves I'm using to replace the old are duplicates, 1.5"x3/8"x1/4". Has anybody used 1/4" or 5/16" line all around? I like the feel of the 5/16" but the 1/4" seems to fit the sheave better. Thoughts? Ian M-17 Seaweeble