No, you don't want to switch between the two week after week. If one leaves you totally exhausted, why would you ever want to follow it in the first place? You said it resulted in overtraining, which I take to mean "no gains."
Trying to do both half-way is a variation on the golden mean fallacy; i.e., the truth is "somewhere in the middle." It's a novel idea on the face of things, but you need to figure out what you need to do to grow as fast as possible. Following some arbitrary set of rules, like Arnold's, don't factor into the picture.
I somewhat like Heavy Duty training when the frequency of training has you nailing each bodypart hard at least every 7-9 days. Beyond that, I'm increasingly convinced that you're not doing a whole lot to facilitate muscle growth...maybe a little here and there, but to really get the ball rolling, you need hard stimulation as often as possible. Doggcrapp's training approach, IMO, is a good way to approach this. You do minimal volume but work very hard, and you provide another stimulus soon enough that it'll force you to keep growing.
Louden, Fatty, and many others have reported on the efficacy of this method's success. I've seen far fewer report consistently great results with Mentzer's post _Heavy Duty pt. I_ workouts, including myself. Even after a moderate cycle, my arms, though a more shapely, have remained soundly stuck at 18" for a looooooong time, even after experiencing some very nice strength gains.
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