I don't think that a pull-out program will help much. My DD gets pulled out once a week for an hour and she really likes it. They do fun things like pentominoes and brainstorming, and they maybe get a chance to think more deeply for an hour, and it may even touch on things like math and reading. But it's an hour out of 32 hours a week of school, so it doesn't help with academics acceleration AT ALL. In fact, in DD's case, they get pulled out during math and are still required to do the work they miss, but on their own.
I was in a pull-out program when I was a kid, and I believe it was three times a week for a couple hours each time, and it still didn't help accelerate my work in class at all. Again, we did fun things like make up recipes and participate in Odyssey of the Mind, which have their value. But it did not help me in the classroom.
IMO, a much more effective strategy for kids working ahead of grade level is to actually teach them beyond their grade level (sounds obvious!) via subject or grade accelerations.
