ive done it your way and it sucks. People are drunk and don't know how to operate a camera, and it's more trouble than its worth.

The better option is buying a cheap mic , plugging it into your dslr and going up to people and interviewing them. You get better audio, can control everything, and you can get diverse backgrounds. Plus shooting wide open looks really cool with dj lights in the background.

Just watch your audio levels on your camera to make sure the mic is actually on. I've gotten home and the bride and groom actually turned the mic off during their speech and it was disappointing.

Message me if you want a link to a couple's video I did with this method.