I can see her as the type of person who would adapt her wedding to the man she was marrying. Not in that she'd let him make the decision about the flower arrangements etc., but so that she'd make decisions that would agree with his character. If she's marrying them for money (which is I think what's implied in the books), then her main interest is to appeal to the men individually. So if, for example, she's marrying someone who made his money in back-to-nature potions, she might opt for a wedding in a meadow, whereas if she's marrying a very high up society person, she might plan a large house thing.
The wedding planning could be something for her to show her future husband just how appealing she is to him, so that he doesn't run out on her before the "I do"s.
She was pretty well-off, wouldn't she? I think it depends on the nature of the current husband--an extremely beautiful witch like her may have had all sorts of husbands, ranging from high-ranking officials to handsome travelers. The type of wedding would probably depend on the nature of the husband, although she was a pureblood, and Blaise was friends with Draco Malfoy, so his mother was possibly in that circle.