Due to the fact that there's actually no visibility about the support of the plug-in and especially an upgrade to make the YouTube videos visible on iPad and iPhone, I have decided on one of my website, after wasting hours and hours finding workarounds and other solutions, to give up at least temporarily with CVG and to move to WP Video Lightbox. Back to the basics.
If you're searching your way to show YouTube movies on desktop computers and mobile devices (at least iOS devices) from an automatically generated thumbnail to a lightbox and optionally in full screen mode (you see that it's a reasonable need in October 2013), know that WP Video Lightbox is actually doing the job (with no conflicts with other plug-ins on my website). Just an optional modification in the "wp-video-lightbox/js/video-lightbox.js" file to set the autoplay to "true" (plug-in wide setting) for desktop computers.
I just desactivated the CVG plug-in in case the author gives us a better visibility with his project and produces a usefull upgrade. I now have to think about moving from CVG another website which is using a bigger number of CVG galleries. That's a real pain.