Yea it does sound like you are doing a bunch of work arounds, I can now appreciate the development time for this. However, the clean design hides all these hacks :) I assume you had tried the youtube IFrame API etc in the background page etc? But I guess if you were to use that then the elements on the youtube player are there and you don't really need it.
That weighting feature for the radio is gold - its kept me listening since I installed it! I had not thought of that when developing my app (https://github.com/viperfx/ng-juketube), I just used the mix's. I have been using your extension since I installed it, I might have to use this and not my own app :) or improve my one.
One bug I did notice is that videos tend to overlap, what I mean by this is that some videos seem to be smaller so you can see the previous video paused or stopped in the background and the current video playing over it - you notice it because the current video is somehow smaller.
I look forward to the updates.