I know I sound annoying but what's problem in asking her about favorite perfume? Yes, its personal thing but you are going to meet this woman for dating, for love, most probably for sex. Taking all this long way to her man shouldn't be shy to ask this thing. If you prefer to avoid direct question it can be done in the form of questionnaire: favorite flower, food, color etc. And wanted to ask girls here who show disagreement with my opinion: when do you think is appropriate time for such a gift?
p.s. word "Risk" is greatly exaggerated