Interesting question. I've recently purchase a Z30 with the DX16-50 lens from a member in the classifieds. I've also purchased the new DX 12-28mm lens as well, and they are not only tiny and very light, but incredibly sharp across the frame and focal length, which I must admit surprised me a little for such relatively cheap plastic fantastic lenses.
So for a laugh, I mounted them on my Z7 II, and much to my surprise, was impressed in only only how at home they felt (fast AF etc), but how lightweight the combo was and the images from the Z7 II (obviously in auto DX mode), looked pretty much identical to those from the Z30 (as you would expect). It got me thinking, with the Z7 II having an EVF, better video modes etc, my question is, it it really sensible to consider something like a Z7 II with DX lenses to get a lightweight (almost pocketable) solution for travel etc - or am I mad.
For info, my FX lenses I would usually take for the Z7 II would be the 24-120 f4 and the 14-30 F4 with weights of 630g and 485g respectively (a total of 1,115g). For reference the DX 16-50 and 12-28 weigh 135g & 205g respectively (so 340g total) - a saving of 775g. even if I add my 24-70 F4 to the mix (for similar focal length), the weight saving would still be 645g ?