i'm not sure if too many snacks will make a lousy character. i give my tamas tons of snacks until they are at max weight and then play games to get them back down. to get gotchi points. i've done it with 2 gens so far and i've gotten a pyonchitchi and chohimetchi. from what i hear those ones are pretty good. and the toothache is easily remedied with a trip to the dentist. my tamas get lots of toothaches. they will eat about 10 snacks b4 they get 1 and then after you fix it you can give em about 10 more. adults don't get a toothache though, and an adult won't evolve any more if you mate it, so i don't think you have to worry about spoiling it.
yummyhunny