Does this make me a 'Zilla?

What you are thinking to do is not a bad idea at all. You're just making something difficult (getting all the girls together on one day) simple instead. I, myself, narrowed it down to two dresses, I emailed the pics of the dresses to all the girls in the bp. I gave them plenty of notice on the date I wanted to go to the store to choose the dress and get measured. Only 2 out of the 7 were able to make it. So, I went with the 2 girls able to go, and then told the girls who coldn't make it the final decision and that they could go get meaured at their convenience as long as it was before Nov. 1st. It worked out well. You're not going about this in a negative or inconsiderate way so I think it's fine to do this.....