Anyway, I'd probably wear the heels but then I'm only 5'4" so need the height. What do you feel more comfortble in? I find I'm more confident in heels and feel a bit like I'm just off to the shops in flats.
If you're wearing the cardi then go for the tighter top. A tunic and cardy might look bulky worn together.
Had a look at your profile and you're ever so pretty. I'm sure you'll look fab whatever you wear.