Hi dmiller:
It appears from looking at your Public Profile that you may have just joined the forum? If so welcome. The participants are always very helpful with excellent recounts of their experiences.
Your topic has come up numerous times with lots of good info already posted within the Cherubini forum ... even very recently (although for a Hunter Cherubini 33). Might I suggest that a good start might be that you spend a few moments and search the forums using the highest most search button in the menu section above.
Notwithstanding the info you find, you likely will need to make some of the determinations yourself. For instance, you might have a sail with the reef clews and tacks at different heights than Hunter's OEM sail. If so, then the OEM specs for the reefing lines won't be correct for you.
If you haven't already discovered, various original Hunter drawings of rigging and plumbing and electrical and also the original manuals have been downloaded into the forum. Being a long time since I needed because I have saved the pdf's directly to my computer, I don't remember how to find. And at the moment I can't do the sleuthing for you. But post again if you aren't successful at finding.
One item to mention is that original Hunter info about line diameter is now largely irrelevant since even in smaller diameters today's line technology permits greater strength and lower stretch with much smaller diameters than when our boats were made back in the late 1970's and early 80's. For an extreme instance, I would expect that today's 1/4" Amsteel would be stronger and with much lower stretch than was a typical 7/16" yacht braid in 1980. But still, and depending on how frequently the line is handled, usually more diameter than say 1/4" is needed for comfort and ability to grip in the hand. Also Amsteel for instance is slick and probably isn't the best choice for using through a rope clutch. If 3/8" (a guess) was originally specified by Hunter as the reefing line diameter for thew 27' model, then depending on the grade of line you choose, today 5/16" probably would easily be today's equivalent. But do the research yourself.