Your usual mousepad is fine for a vertical mouse.

No, the surface requirements are the same.

Vertical mice still use the same optical or laser sensors as a normal mouse. The sensor sits on the bottom, pointing straight down — exactly the same as any other mouse. The tilt of the hand doesn’t change how it tracks.

Some vertical mice might have slightly different feet or weight, but that’s about glide feel, not tracking. A hard pad, cloth pad, or even a desk surface will work just as well. If your current mousepad works with a regular mouse, it’ll work with a vertical one.

Don’t overthink it.