I would definitely need to see one in person and feel the weight.
I would love to be able to hold one also, problem is with Nikon it will probably take over another year before it is available in store

I have really been checking out weights and sizes too. Would like to see the Sony in a store, hopefully some will have actually in stock soon. We own the EM1, dimensions extremely close to Z7, (you could check that in store for a size reference), it is a fantastic feeling camera actually, but yes, once you put on the more pro lenses that weight changes quite a lot. It still seems to balance well with the longer lenses though. It is also quite a bit lighter a body than the Z7, so Z7 may feel a bit brick like.
OMD E-M1vii 134.1 x 90.9 x 68.9 mm (excludes protrusions) 498g body only
Sony A7Riii 127 x 96 x 74 mm 573g body only
Nikon Z7 134 x 100.5 x 67.5 mm, 585g body only.
I really haven't been doing much photography since I sold my D700 for D800.. but am keen to get a lighter, smaller mirrorless that works well for me in full frame, and get me back in the game. I have an 18 month old Granddaughter and another little boy on the way

so really was fancying the eye detect, they move so fast.
I currently own a Df, and a OM-D E-M5, my husband has the OM-D E-M1 ii between us we have a ridiculous amount of lenses. Time to sell some off and get our system streamlined.