Bat size and Brand of bat

Question
My son is 7 years old, about 4ft 1 in and weighs around 55 - 60 lbs.  Which length and weight bat do you suggest.  Also, if you can help on this which bat would you pick between the Louisville Slugger Catalyst and the DeMarini Vexxum?  Thanks for your help.

Answer
If he is 7 I would say dont overspend on a bat.Spend the money on a really nice glove or a really good pair of pants.I think people go way to far when it comes to bats for small kids.At that age does the bat really matter? If you want to find out which bat would be better for him have him try out other guys bats and see which one he likes and go with that one.