Welcome to Visual WebGui
Firstly, when you are "calling" Visual WebGui using query parameters, you should preceed the form name with a "post." prefix. For your first url, this would mean you should use http://www.website.com/visualwebgui/post.visualwebgui.wgx?value=1".
Inside the application, you use VWGContext.Current.Arguments to retrieve individual query parameters, so script attacks are not really possible if you validate the parameters. In any case, you can encode the query parameter string in what ever way you choose, provided it has valid query parameter characters after the encoding. You could even base64 encode the whole parameter string, but you would still need one parameter, like for instance
If needed, you could even throw in a checksum or some other means that would make it possible for you to guarantee the validity of the query parameters.
If I misunderstand your point, please explain further.
More on Query parameters here.
Hope this helps,