The "strength" of the covers you're using are the characters. That's a strong point for your Mc Quarrie backcover of SW 77. So for Empire, well done for the colors, but the somehow pristine painting of Mc quarries doesn't worth a penny next to the sandmen you used before. But well, maybe it's the only option, I don't remember all the paintings. The space slug one would have been great (same dynamic - direction), but would ask to altere the colours...
PS: the edges are great.