Try hitting utter failure in 8-12 reps than move to the next exercise without rest for 8-10 exercises. Doing (large mass involving) exercises like squat, pulldown standing press etc. You won't just be tired but in a state of shock. No matter what kind of training you did before if you never trained this way the first time you try you'll probably and up on the floor after the first 4 exercises.
I trained with many people and the result were always the same. Either they tried real hard and ended up on the floor or puking in the toilet or they didn't try real hard.
This is exactly how I workout, once a week (max twice). Usually I can't handle more than 6-7 exercises though, otherwise the result is "ended up on the floor or puking in the toilet". I guess too much lactic acid build up than the body can process, because of the very short rest between exercises.
I'm not measuring reps though but time, using weight that I can lift until failure for at least a minute/minute and a half. That way I can do them slower/faster as I feel is right and still have a good measure of progress.
But still, I haven't had such a huge weight gain like you (10kg muscle in a month = 333g/day). Maybe it was because I was eating SAD back then. Maybe because I have a much lower starting weight of 75kg (I'd think it's better to measure weight gain in percentage increase instead like this).
Well let's see how it goes now on this diet.