my daughter had an oniontchi( u get him from neglect) and she had overfed it to 99 lbs. so i started excersising it with bump. was amazed to see it winning most of the time and oniontchi actually made champ(8 rnds)! they do better when they are heavy, yes, but i think it also has to do with the character you have and the one who is opposing(i've heard the old timers don't like to be beat by a younger tama, and i don't think i've ever beaten one) oniontchi, because of his neglect, is prob a tougher character. the tamas that i have pampered don't do well at bump no matter what their weight. but oniontchi would win even if his power bar had no black at all! and even when his weight started to drop back down he still did good. i think diff tamas are better at diff games.
yummy