^^ might be kind of hard to get it to look natural. plus lightener is naturally going to work more quickly towards your scalp because of the heat, meaning that the natural tendency is going to be for your hair to be DARKER towards the ends and lighter toward the scalp -- a mistake i'm sure most of us who have ever bleached our hair at home have made, i know i've definitely done the 'oh crap, gotta re-bleach my ends 4 more times' thing before -- which is the opposite of the look you want.... i'd say it'd be best to just let your whole head go lighter and then just wait a few months as it grows out etc.... i imagine it's quite complicated to hand-paint highlights on half of your hair and make it look even and natural.