I have a feeling it works great on a smoother surface

Mske sure you clean the mounting surfaces well and press for a minute, don't mount other parts until adhesive cures.

It did not stick to a rough curved surface in my Hyundai Elantra

You MUST use this on a smooth surface

You need to make sure the surface is smooth.

It just doesn't have enough surface area for that.

Adhesive did not hold on a VERTICAL, hard plastic surface, in a hot car

The adhesive base is large, so you need a good size flat and hard surface to mount it to for it to work properly.

I have plenty of room to mount the Base onto the middle of the hard flat surface on top of my dash

There is just not enough surface area for the amount of torque this sees to get any kind of adhesive to work