Reef the Main first
Catalina makes masthead rigged boats. Typically, it is best to reef the main sail before you start to roll up the Genoa (although that's easier to do). As for when.The stock answer is "before you need to." Not much help, but true. Most boats sail better, more comfortably, and faster when they are sailed FLAT. Do what you can to depower the sails first, then when you are overpowered again, reef the main (10 -15 degrees of heel is a good target), then roll up the genoa a bit (120 - 130% is a good starting point). If you have a second reef, do that next, then roll up the Genoa some more.If that's not enough, get off the lake, the wind is too strong.Most people seem to start to reef their mains at about 15 - 20 kts, but some do it earlier, and some do it later. In 2000, I did the first three races of the C-30 National CHampionships with a reefed main and full genoa in 20 - 25 knots. Won all three races, then sat the fourth race on the sidelines (had one throw-out).SteveC-30T Alchemist #4764C-320 Alchemist #909