I ignored the minimums and use the largest size I could fit thru the lifeline grommets of my boat. I think it was 1/4" but it may have been 5/16 or 3/8. It is an intersting issue since the chaff guards add a lot more chaff resistance than upsizing the line, but the extra line size adds a lot of safety margin. For my cruising boat I went with the largest size possible. For a race boat I would probably go with dyneema chaff guards on the minimum size line, for a cruiser the largest size that would fit.