The ZYX will precisely split the difference between the slightly warm or thick sound of Benz and the slightly cool or thin sound of your Lyra. You've already heard both sides of neutral (not the extremes, by any means). That should give you some idea of where neutral lies.
The Airy 3-X-SB will give you all the detail and speed of a Helikon, maybe more, with slightly more weight in the mids and upper bass. It won't have the upper bass/lower mid heft and thickness of a Benz, but it will have more extended and cleaner upper mids and highs. It will give plenty of "kick". The Airy 3-X-SB is a lively cartridge.
The Airy 3-S-SB will round off or gentle leading edges a bit, bringing it a trace closer to the Benz side.
The Airy 3-X-SB will give you all the detail and speed of a Helikon, maybe more, with slightly more weight in the mids and upper bass. It won't have the upper bass/lower mid heft and thickness of a Benz, but it will have more extended and cleaner upper mids and highs. It will give plenty of "kick". The Airy 3-X-SB is a lively cartridge.
The Airy 3-S-SB will round off or gentle leading edges a bit, bringing it a trace closer to the Benz side.