At 135lbs Katie Taylor is the best there is in the world of boxing. She is ranked #1 pound for pound in the world. Valentina is the best at 125lbs and has had fights earlier in her career at 135.
I like that rule set, it would be semi fair.
Kickboxing Valentina destroys her and boxing Katie destroys her so that would be a fun fight but I doubt Dana lets her take the fight because then Valentina will realize she is being under paid