Don't worry about trying on before you buy.
I know catalog companies are pretty liberal with returns, even on bathing suits. Just go to google and do a search for bikinis and/or swimsuits and a tons of sites will come up. Of course make sure and ask what the policies are and who foots the bill for the return postage. I got mine from JCPenneys last year and didn't have to pay the shipping because they didn't have them in the stores yet. I was able to order it into the store or have it delivered at home. I think if you have it delivered to the store you don't have to pay for it until after you try it on and decide to buy it. Again I know stores are all different so ask up front.
Good Luck! and Have fun.
81 days away from Carnival Victory - Western Route