Going on vacation with my gf and I want to propose. Unfortunately, I''m not going to be able to get her the engagement ring I would want to give her in time. How tacky is it to do it "backwards" and give her this diamond band (http://www.bluenile.com/diamond-engagement-ring-setting-white-gold_4783?nav1=jewelry_segment.jsp&metal_filter=white&band_filter=with_diamonds&show_all_pages=1&catid=126&set_shape first and give her a diamond solitare on the wedding day?