I actually think the Xitone 12 passives would probably work well with my matrix GT1000FX.
Where do you put your AxeFX when you use the ZLX?
I have mine in a 4U soft rack case with a power conditioner. I used to bring a stand for it, but now I just plug the cables in and then stand the rack on it's back, facing up, and put it in front of me. You can see it in the video I posted - it's to my left and in front of a house monitor that's facing me. ZLX12P is behind me standing up.