I’ve seen 4 or 5 people stack an OG telephoto cam on top or to the side of a Pan V3. I ran a quick search to link you to one of the examples, but they didn’t pull up for me easily.
As I recall, it works okay, though it can strain the pan tilt motor some. Most people I saw didn’t use duct tape, but some other kind of adhesive solution (double-sided tape, some kind of glue, etc…I didn’t pay close attention).
If you end up trying it too, you should post a picture/video.