Hair Trial/ Tiara Question

I ordered my tiara from Kleinfeld's but they told me they do not make it come in until closer to the wedding. but i have a hair trial set up for August b/c i want to make sure i like the way they do my hair. but i do not have the tiara!!!! what do it do???? Kleinfeld'd told me they can put a rush on the tiara, but then i assume all responsibility on it b/c it is so far from the wedding date!!!! What does everyone else do????
ALso, is it true that they tiaras can some dulll/tarnish if they are made too far from when they are being used. i mean, i spend a lot of $$$$$$ on it and i didn't think it should tarnish so quickly!!!!! Someone told me that and i wasn't sure if it was true!!!

I would put the hair trial off and wait for the tiara. You have enough time left