Using the virtual shelf feature
First, please note that in order for the virtual shelf feature to work efficiently, your desktop color depth must be in 32 bit or higher.
Working with virtual shelf is very easy. Virtual shelf uses the group field to determine how the item is going to look like. But you don't have to open the item edit dialog to change it. Just by right clicking an item, you'll find available looks in the Change Case sub menu.
Please note that you can select more than one items in order to do a batch update on the looks of several items.
Regarding the live zooming feature, by default, the zooming factor will be set to 100%, preserving the highest available resolution and quality of the supplied item looks in the theme package. You are advised to set it to around 85% to get a decent overview because more items will be displayed.