it’s generally hard enough matching different cameras but in this case you’ll have your work cut out i think; different sensors, glass, etc.,
i often shoot with an ex1 and whatever other camera comes to hand (i have a z5 too, which comes close, but not close enough – but that’s often out when i need it ;-(). i’ve been using my nex7, along with the neighbours jvc, and simply give the 2nd camera a completely different look, more often than not, b&w, camcorder overlay with tc running, and perhaps a bit of software induced ‘movement’/ gives the feeling of ‘immediacy’, doco style…
good luck anyway..