I'm getting flashbacks to Tomo-chan wa Onnanoko and Misuzu belatedly realizing that generically telling someone to be more girly to attract the person they like, was actually really dumb.
This time may not be that bad, but—like, you really think the young, fairly patient, science-loving boy is going to care about how many sugar packets she uses...? A makeover might work on him, I suppose, since he seems... not-immune to the proclivities of youth. But the whole "Be even less like yourself!" aspect of the plan doesn't really seem like good forward-thinking...
I suppose it makes sense within the motivations and known weaknesses of all the characters, having said that. This is not the cool, suave, wingwoman best friend. This is the spoiled rich friend with a few inherent personality flaws who is trying her best to help you.
Luckily, our protagonist is almost definitely completely incapable of maintaining this sort of shallow facade. So hopefully it'll be fine.