Thanks Bagginsbill - yes, crossposted there.

I'd also been thinking along the lines of how to reduce the need to render the whole thing at that massive resolution.

For a ground level camera, the sky will always be distant.

I was thinking that for the sky, which is all pretty distant, in that style of image, rendering out at 4000px by 2000px would be plenty. Less than that may be plenty...

Rather than necessarily doing anything with UV maps I could always then blow that up to 10000px by 5000px in Photoshop and composite it with higher res foreground ground elements or whatever. Photoshops resampling would probably compensate anyway... but also I could gaussian blur the lower res sky too, to effectively upscale it?

I'm pretty sure Photoshop can retain the hdr information from the output Vue renders...

But the solutions you've proposed using dual maps or a non-homogeneous mapping sound like they'd also have the benefit of using less Poser resources?

Having the different panorama elements controlled by shader nodes could allow all sorts of other mat room adjustments too I'm guessing?