I'm using a shotgun mic as a backup form of audio for a wedding I'm shooting this weekend and wanted to know if it's best to get the mic really near the couple and aim it straight upward or to put the mic back a little bit and aim it on a horizontal angle towards them.

Which way would produce the best audio? I know this isn't technically the right forum, but I have only a short amount of time and you guys have been really helpful in here. Please let me know if you have any thoughts! :)

Thanks in advance!

The tried and true Senheisser ME66 is a good choice. It's a very hot mic- you might even find it too hot for your liking. I personally had the red-dot mod done to it to make it less sensitive.

In a wedding, if you want to avoid the audience noise, point it up and between the three main players. Horizontal will work but with three people standing in a triangle, one (with their back to you) is going to be a bit muffled. You will get the voices in any case.