I agree with the crowning glory - spray your corsages and the flowers will stay nice and firm. We had one dendro corsage left over at prom time (someone meant to order a bout over the phone, long story) and by the next weekend it looked almost exactly the same. It was in and out of the cooler, worn for fun by several designers over several days. It's nice to see how well they do hold up when you recommend them for things!
PS - I had a mini cymbid that I was using for corsages recently. One bloom was broken from the stem, so I put crowning glory on it, boxed it and put it in the cooler. When it came time two days later to assemble the corsages, this broken one felt more firm than the blooms that were still on the stem, in water, in the cooler!