The easiest way is to use a radio button TV that will return a value that you will use in the template's stylesheet link.
<link rel="stylesheet" type="text/css" href="assets/templates/css/[[*color]].css">
You can change layouts by adding a classname to the body tag, again with a TV, to indicate the type of layout, then use specific CSS directives to show/hide/position the various sections of the template.
Alternatively, you can have three or four templates, one for each layout type, and assign resources to these templates as desired.
You can use access control permissions to control which of your Manager users can see the TVs or edit the templates.