Florists

I have a couple of questions. My wedding is next September and I would like to have a sunflower theme. I was thinking possibly large sunflowers in cobalt blue vases on the tables and bouquets for my bm just large sunflowers with ribbon and mine more exoctic - orange calla lillies and other flowers mixed in. I've been told that sunflower bouquets wilt - what is your experience with them? Also, if you could give me an estimate I'd appreciate it:
1 bridal bouquet
7 bm bouquets
2 jr bm bouquets
1 flower girl basket
1 groom bout
8 groomsman bouts
2 usher bouts
3 mom flowers to hold (a few w/ a ribbon)
2 grandmother corsages
3 dad bouts
approx 20 centerpieces
Thanks!