For once I'd be happy if Naruto remained stubborn and didn't listen to those words. He should instead use the Kyuubi chakra as much as possible and perfect red rasengans.

Anyway, three per day sounds like a totally artificial limitation put in place simply because Sasuke (or Kakashi) can't use chidori too many times and thus it would be "unfair" if Naruto could use rasengan as much as he needed. What comes to the practice rasengans and their numbers, it doesn't really make sense. He was surely wasting a lot of energy with them, instead of them not, supposedly, being full power. It's not a raw force technique like chidori so the better he can do it, the less energy it should take for the same effect. It makes zero sense the poorly formed ones spent less energy and still shattered places.