Ok, I know many of you have asked around with dealers, manufacturers, and retail shops, coming to the conclusion that no other towers will work with the OEM rails except for the ones designed for the VX by Yakima.
My nextdoor neighbor (a good friend of mine) is the service manager over skiing, snowboarding, and mountain bikiing for GI Joes in Oregon. He had a spare Yakima 1A raingutter tower that we decided to test on the rail to see how it sat... low and behold it fit just fine! Now, we only tried one and didn't get a chance to set up two with the crossbar, so I'm not sure if the entire setup will work.
Anyway, I'm trying to get a whole rack to test-fit to see if I can get this setup to fit properly. If so, this may be a much more widely available, much cheaper option to consider. I will keep everyone posted.