Brilliant Eric. When I was going over the VLB code trying to figure out what was keeping things from working, I had come to the conclusion that the thumbs had to be separated out somehow, in order to become responsive, but couldn't figure out how to do it. Nice solution. I can see what you did in the RSD file to make it work. I will have to study it a little further to make sure I understand all the nuances, but seem fairly clear already.
Yeah, I had contacted VLB support, and they did email me back, but their answer did not provide a solution. I even mentioned to them, very tactfully that their demos on their website, that the thumbs were not responsive, but they had no response to that in the email.
My conclusion had been, after many hours (and many days!) of trying to get it to work (without mods), is that the code the program generates will work fine if it is set to auto and then none of your thumbnails are bigger than the smallest mobile device. It will stack and work fine. The majority of website examples I've seen in the forum here, are in that category (and the vlb's I had done up to this point were in that category as well), so the problem with thumbnails not being responsive won't even show up.
So actually, it was a good thing Ernie's project had the larger thumbnails, which exposed a nagging problem and pushed for a solution. An elegant solution. I played with the settings in your RSD file, and now with the way you have it set up, one can completely control the layout of the thumbnails, however you want them and totally adjust how they size, resize and stack, etc.
I think this solution you came up with is going to come in very handy (until CC comes out with their Lightbox! I'm sure it will be awesome, easy to implement and will work right out of the box! lol!).