That looks pretty cool! But I have a couple of wishlist items for it!

I have a whole bunch of HDRI images. When I go to pick them, it would be super helpful to see some thumbnails so I have a general idea of what I'm getting. Often I have to try a few before I get one I like.

Second, since you can rotate the Y axis and you can also rotate the camera, it's really hard to know what part of the image you are looking at. Poser 13 has a dome that can be used to show your HDRI background, but it doesn't sync if you manually rotate the HDRI image. It would be incredibly helpful if your script could set up that dome and the XYZ controls handled both the HDRI background and that preview. If you add that, I will buy it for sure!