Not sure if this will help you or not, but I am playing with VBM for a redesign I am doing: http://saviodesigns.com/saviodesigns-redesign2017/index.php
What I did was add the Video Background to an LBM rom, then made a nested LBM instance with two rows: the first one with 2 columns (for the logo and the "Request Quote" button, and the second row with one column for the Tagline Text. I have the tagline text in a div that is set to align at center, and I gave it a class for stylizing the text.
It seems to work well for me.
Any normal way you would use to stylize text/etc. should work as well as the VBM is a background, so however you would center the text in your div/etc. should also work fine,
I hope it helps you!