Playing multible tournaments at the same time

I was reading Rizen's Poker Blog and he plays 5-8 tournements on 3 week days, same thing on saturday and around 12 on Sunday.

I understand that if you want to make money from MTT you can't play only once at a time and when you bust start a new one. you need to play a lot to win a lot.

However, if you play 3 tables at the same time I don't think you can get as good reads as if you played only 1 table at a time.

Is there a right balance or depends of your style or do you only play your cards?