It's the weight you feel most comfortable making and ENJOY making. When training camps are more than 50% focused on making weight then there's a problem. Working on a gameplan should be the main focus. A good example is Hopkins going to light heavy for Tarver, you can see in videos and clips during his training he was ENJOYING every minute of the process and loved the idea of eating good food comfortably without worrying about keeping things balanced. Some enjoy it and some hate, all depends on the body.
Floyd would stomp JMM even if they were in the same weight division:deal JMM just doesn't move his head.