Hi Chris
I would put the surround speakers higher with the tweeters somewhere around ear height when standing. The rears in HT are responsible for the ambient sounds so you want the sound to be more diffusive and not so direct. My set up with the four 1Cs do sound a bit like they are coming from the speakers but it would have been a big eye sore to raise them in my room. You have a lot higher ceiling so it is ideal.
I never tried the VCC1. Since you have the Quatro, I would favour the VCC5. If you look at Vandersteen's forum, he always recommends the VCC5 with 3As and up as they have much greater dynamic and sonic capabilities than the smaller VCC1.
Acoustic treatments are a good idea and one of the most effective upgrades you can make. For a HT room, you want to control the reflections as much as possible so I would also add some side and rear wall panels. I originally started with the ASC 1/2 rounds at the first reflection point, but I recently added additional ASC CinePanels and the sound become more focused with better clarity. It is a lot easier to understand dialogue and the sound is just more natural and less fatiguing. The CinePanels look great, are easy to install, and relatively affordable.