best way to reef a main
It really depends on the set-up on your boat. If you have slab reefing with a reef tack line as well as a reef clew line you can often reef on the fly on any point of sail. In that case, close reaching is certainly preferable to being head to wind in that you maintain control of the boat and do not flog your sails as badly. Depending on the conditions, rigged so you can reef on the fly, even though there can be a lot of friction, reefing with the boat almost dead downwind can sometimes make sense because you have less aparent wind and you don''t have to flog the sail at all. Again it all depends on the conditions, the size of the boat and how she is rigged.