In the movie My Girl, the spelling is Vada, which might help people to pronounce it the way you want it to be pronounced.
This name was on our list before we were even TTC. Then, the Star Wars movie was coming out, so we decided against it.
I do love it, but I would be so sick of people and their Darth Vader jokes and jibes. We live in Australia, so Vada and Vader are pronounced exactly the same.