OK here are the params: HDR off, DR on 'high', shadows on. PBR fuse materials created via ModelConverterX, other materials still FSX. Albedo and Normal (bump) texture size 2048, Metallic texture 1024 only, Red (metallic) channel white (full strength), Green and Blue channels passive (white and black respectively), Alpha (smooth) blotchy mid-grey.

As you can see, the tailplane does cast a shadow in the present environment and light angle, but that is the absolute exception, in most other conditions there is no shadow or just the faintest hint of it, supporting Harley's findings, above.

In other respects it doesn't look too bad, except with the metallic alpha (smoothness) at 50% the dynamic reflection remains fuzzy and indeed hardly noticeable at all. Of course, pushing smoothness up to 100% gets you full and sharp reflections, but then the spread of the highlights gets extremely narrow, and the rest of the fuse gets awfully dark. IOW, doesn't look good at all.

My question, is it even possible, given the present V 4.5 PBR setup, to render a plausible looking polished metal, including shadows and sharpish reflections and if so, does anyone have the recipe for it?

Alternatively, may I put this on the wishlist: give the developer better control over the spread of the highlights and the amount and sharpness of reflection.