Shortly after I started using actual tanks -- a T3S -- I wanted to switch to my regular Virginia from my "morning mix" that was predominantly apple-cinnamon, but I didn't want to take the time to clean the tank (it was the only one I had at the time).  So I just emptied the tank, and put in my Virginia -- and whaddyaknow, it tasted great.  So now I always add a bit of Oak Barrel Cider (6%) and cinnamon redhot (3%) to my Virginia -- even now that I'm starting DIY, I still add the 6% OBC and 3% redhot to the total mix.  I've started DIYing cinnamon redhot, and it comes out great, but it's going to take a while to find a flavor to replicate that tart-cider flavor of Oak 
Barrel Cider.
Andria