Remember they're YOUR models, you have to look at them, paint them, and play with them
With that said there's nothing wrong with reaching out to fellow gamers for input
I'm assuming since they're Baal preds and Blood Angels, the fast attack is half orange half red helmets?
If that's the case you can do the tanks half red half orange - seen quite a few of those and they look cool. Or a quartered design like the Howling Griffons chapter:
For the lightning you can start it at the viewports of the tank and extend it back however far you wanted to make it look like they're coming at you lightning fast.
Just ideas - show some pictures if you can!