1) I think JP facebook page today got a picture of how different carats look on a hand

how big is her finger though? A 0.5carat covers like only 30% of my finger.
2) means your filagrees don't too kuazhang? anyway some girls like solitaires cos classic, some find it "boring". Maybe can consider side melees. This you have to probe more ahaha maybe show her some pictures, listen to her comments and work from there. Eg: ask her, This one not bad hor? If she says eeyerrrr then you know haha out.
3) No shape is better than one!

super ideal is just the best of round ones. So doesn't mean you get any other shape it is "lousier". Depends more on cut!