Hello: Is there any generally agreed upon size that is preferable? Small (4") less intrusive, but can you get your hand/arm in near when needed for repairs? Large (6") more finger roomy, but noticeably larger. Or do most folks go with the 5" compromise size? My 1966 boat should be ready to take to the water next Wednesday for the first time under my ownership. I plan on installing 1 or 2 ports at end of summer to get the last moisture out and to have for some in hull work later. Leads to the question where to cut one in order to replace the bow handle backing block, obviously it can't be in the "ideal" location behind the spray skirt, maybe 2? 3? John