If you are creating many map tours with the same look and feel (color scheme, logo, etc.), another option would be to download the source code and modify the index.html file with your custom CSS and logo and host it on your server.
From there, you can create a map tour with the interactive builder in ArcGIS Online. Once you have added the photos and text, you can use the appID that you see in the URL and append it to url of the map tour hosted on your organization's server. It will use all the application data that you added through the builder and always allow you to edit the app through the builder but the color scheme will be overridden by the new code you insert.
An example URL might be:
http://www.sample.com/map-tour/?appid= 18ea32008c3f43a898096f4e30e85e79
Any time you create a new map tour, you can use the same URL but just switch out the AppId (in red).