I used the 2-disk Horstman for the can class and, later, for the Y-Pipe. I was completely inept when it came to adjustments–all I did was service it between track days. Needless to say, it eventually became unpredictable to feel when the clutch would engage, and in my ignorance I thought it was the fault of the clutch, that it worked for the can but was less effective for the Pipe.
One day the drum broke, and to me this confirmed that the Y-pipe was just too much for the 2-disk to handle (I was wrong). So I borrowed a fellow racer’s 3-disk dry clutch (a Patriot). It worked much better than my 2-disk and was more robust, so I arranged a trade (after replacing the broken drum with a new one). I’ve been satisfied since.
But I’ve since been told that the 2-disk is just fine for the Y-pipe. In fact, I’m the only one at my club who uses a 3-disk.