Thank you for your response - I am only a part timer so my answer is late.
I tried using your approach wich worked, but it gave me an indexed array instead of an associative array, which gets confusing when using a few variables. In my case, this means 8 variables/settings and counting.
As of now, the webservice version is working as I already use webservices in my plugin. The settings I want to retrieve here are for my plugin only which means that there should be no security risk in returning unwanted/unauthorized config-settings.