Correct.
You’ve set the rig to a channel. That channel is not live. Make the channel live and you get a “good” payload.
Looks like what you describe might be a bug. As editing one value in the rig causes a full payload to be returned.
Your best solution is to change the view to use a channel that is live and use live data. (Or make the channel you already have set, live)
If you need display Resolution in order to control sizing of your extension there are other options for this. (Get the size of the iframe)