You don't even have the right amount of time for a grey, let alone a cockatoo. They need 3 times the attention that a grey or amazon would need and if they don't get it not only will they make your life miserable but your neighbors miserable too. Think Jet engines...thats how loud they can get. Plus, without proper training and handling the larger cockatoos like the Umbrellas, Moluccans, and Greater Sulfurs will turn into pitbulls and bite whoever they are not happy with, and their bite is probably the worst of all the parrots.
Baby cockatoos love the cuddling but it is a VERY bad idea to touch them under the wings and back once they get a little older...it's basicly sexual play to them. I get bit at work by cockatoos because customers will walk in and the first thing they do it start stroking the "hot zones" and get them fired up. When they stop the cockatoos get frustrated and start screaming and because we know that they are no longer safe for a customer to hold we have to take them off the floor and sure enough we take the heat and get bit.