Hmm, in the 'good ol days' a quality camera lens mount was made from machined stainless steel. The mounts on my old high end Nikon film cameras are still really
As s/s is very hard it is difficult - or rather expensive to machine to fine tolerances, so the camera producers started machining the mounts from some sort of brass, which is quite soft relatively speaking, and electro-plated them. On a well used pro's camera you will often see the plating wearing off the mount where the surfaces mate together.
Theoretically a very tight fitting lens will create more wear, but as it is brass to brass, and very evenly mated surfaces its gonna take a long, long time.
Personally speaking, the tighter the better for me, so I
would be quite happy
And looking on the bright side it's unlikely you'll have to join the 'my 24-70 fell off my mk3 and smashed' thread !