Some fun little things I've done with my Ghost Viper set with Crystal Ball:
Use the left "beast" hand for Crystal Ball, it holds the titular crystal ball a lot better.
Attach the backpack hose to the guard on CB's sword so it looks like the backpack is fueling the green flame
Attach the gauntlet flame effect to the hose's end as if it "broke" off of the weapon and is spraying wildly
Prop the beast heads on the nubs of the backpacks almost like "summoning" heads.
Overall, I really like this Ghost Viper. I'm a little bummed about the price tag, the bicep cut and the horizontal wrist hinges. I love the backpack and hose, and the default head. He just looks so loaded this way. I think for $25, Crystal Ball was the better product, but dang if this guy doesn't look even cooler than CB. Take the best new sculpt of the year (Retro Viper), give it a colorful transparent hose, and you've got a contender for Classified figure of the year.
One last thought, I really wish they would have given GV a fire axe to fit in Barbecue's backpack slot, like maybe with a black handle and transparent green blade, would have been sick!