Every bird is different. I have a yellow nape couch potato and he is in a 40x30 HQ dometop. He doesn't use the whole cage even though there are toys all over. I have considered putting him in a smaller cage. It has only been six months so I will wait another year and see how he does before making the decision to move him into a smaller cage.
I do not recommend an HQ cage because of the poor quality of craftsmanship. On top of the other problems I was experiencing with the paint, one of the wheels pops out at the bottom whenever I try to roll it for cleaning.