from what I've seen here, 30 hp seems like a stretch.
In my two cycle days, we ran a three disc, some ran a four disc, and there were those who ran a two disc. I don't remember seeing any advantage with any of them. I definitely didn't see any disadvantage. If I had to choose between a two disc and three disc, I would choose the three disc. Not to get into an argument about acceleration between the two, it's been discussed, (compared to a 360 pound kart and driver, I don't think it makes any difference at all) I think three disc can better carry the load. I have no proof, just 50 years of experience.