If you want to grow small stealthy plants while using auto's, you should probably try to lst them so you can get 10+ tops without hurting the plant at all which can be detrimental to auto's if they dont take the time to recover before switching themselves into flowering which will get you next to no yield.
You can keep the entire plant under a foot tall and have full sized colas. Theyll just be starting abotu 1-3 inches from the soil level if you train it well.