It really is a personal preference. Do you or your intended like bezel..the thin round metal look? If so,go for those, they make the stones look bigger..extra perk. Or do you want to be able to achieve the maximum look of the stone, set it into a prong set or a basket head. Prong set will be higher, personally I had a pair like this and they drove me nuts, they kept falling against my ears. Now I have basket set and they are much more flattering to the earring, set closer to my earlobe itself.
BTW I would also advise going white gold over platinum for something such as earrings unless you have a particular reason for plat (e.g. white gold allergy). Reason being is that sometimes the settings can be more pricey in plat for no particular extra benefit. But if you can get them for the same price, then go for it.
Search online for earring settings, you'll get alot of hits. I would prefer basket setting personally...having had both. Bezel is not as classic as the regular basket 4 prong setting in my opinion.
Good luck!