I think you just didn't cook it long enough, and next time I would use a butt instead of a picnic. They are very forgiving & temp fluctuations between 225 & 300 are acceptable.
I smoke my butts at 270-280.
Other than that it sure looks good!
Nice video! Ive been wanting to try a couple you tube videos.
I am not familiar UDS, but I use a FireBoard thermometer with a fan controller, Automatic Temperature Control (ATC) on my COS. Its pricey, but well worth the investment... basically maintains the temp for you. I agree with Al, butts are where its at. I still do picnics, but I always remove the skin. (I know this defeats the point some lol)