I really like the massive cola I naturally get from to top of plant. I consider it my pride and joy. I always save it for last to smoke and to brag about. So, if I top plant do I get 2 big monster colas or do I lose and get 2 medium colas???
IME whether you train a plant or not you will get similar yields. Based on that if you have more tops they will be smaller. Fewer tops and will be larger. Just my experience.