The only way to know what color your juice is going to be before it arrives would be to ask the vendor.
I have about 30 flavors from different vendors. The only ones that are dark are coffee based (2), root beer float, and tootsi rolly. I think what you & I have both read about darker colored juices causing clogging is a myth. At first, I believed it because I do have a lot o problems with one of the coffee flavors and the root beer (both from the same vendor). I use cartomizers and neither of these juices seemed to wick well and they seemed to need higher heat to work. Otherwise, I was just sucking air. However, I have no problems at all with the other coffee flavor and the tootsi rolly (two different vendors, neither the same as the other two dark juices).