That would be a fine set up. Question, do you have an extra room for veg? This will help you to have a turn around every two months. With 24 plants you will want to veg them at least for a couple weeks if not more especially growing in dirt, I would try to veg for at least a month, unless you are really diled in on your strain and nutes. I would take a 400w MH or one of those 600w's and set it up in another area to veg the plants for about a month and then when the main flower room is done you can throw them right in.
If you just want to have 1 room where you do everything you will take about 3 months or a little longer between each harvest. I would use 3 of the 600's for veg and throw all four in for flower.

You should easily be able to pull over 1 ounce per plant with a set up like that, if not then you are not even getting half of what you should. with 2400 watts you should be able to get 2 to three pounds fairly easy IMO, and that is with most strains such as AK 48, WW, white righno, block head, bubble gum, big bud, hash and the list could go on
Well, hope all of this helps a little.
Adieu