To make the box more narrow when there is only one will require modifying the template. The template is setup so that you can control how many products are displayed per column, and because of this, products will stretch to fit the space.
The settings under Preferences > Page Defaults, are only for pages going forward, they don't change existing pages. If you want your product images to be centered, you can go to Products > Edit Product Info, and select "Center" for the image alignment.
You can add space on the more information pages by adding extra <br> tags in your product description, or you can modify the CSS to add space always.
If you want the SKU to show up in some places but not others, you would need to modify the template. Otherwise, if you choose to display the SKU it will show up wherever the product shows up.
Many ShopSite themes don't allow multiple columns in the search results. Only newer themes use this feature (ie. simplicity, ship shape, lights, roller, etc).
- ShopSite Lauren
Contact me for help with any of your
custom ShopSite template questions.