Good afternoon, Andy
I saw your video and really like the design of the watch. Personally, I'd improve the video by removing the subtle shake, making the hands move while the watch is turning, letting the watch make a full rotation before restarting the loop and maybe adding a bit of a lens flare when the watch is at a certain angle to give it more shine.
You said that you'd like to be able to change the background so I'll render out a png sequence and convert it into a video for you and send you the Premiere Pro working together with the rendered video.
If that sounds good, let me know and I'll start right away
Thanks