When I said that I'd try to MU these two when I got the VL BB, I was asked to post photos and such. Well, here they are.
As you can see the KL BB is very small next to the VL BB. I did try MUing them, with the KL BB being the lead unit, but I think it wouldn't work very well as it traveled faster then the VL BB, so it'd be trying to pull it around. Sorry, no video of that as I was busy trying to keep the KL BB from rear ending the VL BB. But here is a video of them running side by side.