Right- no problem with six, or five, or four, for that matter. A number of us in here have experimented, successfully, with cycles like these. Three-days are good for those who tend to overtrain or whose schedules don't allow for more frequency, or whatever. But if you have the time and the stamina (and, a six-day doesn't/shouldn't have to be high volume, you know), go for more frequency. If you're a beginner, though, I'd stick with three-day at least for the fist cycle or two till you get used to the program.