Another reader suggested pairing as the Earth-Two detective goes up against the time travelling pulp heroine from Tom Strong’s Earth! And why is Jonnie Future yellow? Because of the original cover!
Thanks to regular commenter Dale for suggesting this.
Crisis on Earth-Prime 
Wow, I’d forgotten all about that suggestion. Glad you decided to go with it. I wonder what a Jenny Sparks & Jenny Quantum involvement would mean for this particular pair.
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