I definately think you should do it, like you said earlier try a mock up and see if you like it and if you think you would have the time and patience to make however many you need.
But if I had any talent in that department I think I would definately give it a go and I would imagine it's cheaper than buying out of the shops, well the bridal shops anyway.
Another plus side is they will be 100% unique to you and your wedding, no one else will have the same dresses!
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