I have the Auris Nirvana, a close relation to your amp, and it’s fantastic with the VC and AO.
In the end, every amp has a voicing. If you’re wondering whether you’re currently missing out on anything with your two ZMF headphone, you can be comfortable in having a great pairing on hand.
That said, every tube amp will sound a bit different than another, and any tube amp voicing will vary a bit with tube rolling. You can (and may) experiment forever and enjoy it. Or just park yourself where you are if your amp gives you the joy you were hoping for