Problem with creating UniformGridPanel and rotating 3d mesh widget.

I have problem with adding slots(buttons) to my widget. In invenory i have 11 items but in the screen i see only one, very small. How i can add space between dynamic created buttons in UniformGridPanel?

And i wanna ask about how i can adding 3d model to widget and create events to zooming and rotating. Something like in image.

Thanks guys.