M_Boats: rigging internal halyards

Hi, all -- I have been lurking on the list and tinkering away on upgrades and fixes on my M-17. Thanks for all the good advice and info! I want to convert to rope halyards and have modified the sheaves of my old (1975) masthead to accommodate 1/4-inch line. The sharp bend at the masthead to get the line on the sheave is too much friction, so I am planning to rig internal halyards. Anyone done that? How best to proceed: one or more holes in the masthead base? There could be 4 lines (3 halyards and a topping lift) -- is that asking for trouble? Any advice or shared experience will be much appreciated! Nick C. M-17 #69 (one of them)