Well, I don't think the video was that bad but I agree it's a bit too long. I don't know if 10 minutes is the sweet spot necessarily. Something around 15 minutes would be ok in my opinion. I agree on the points you made. Teaching how a uke can be tuned using relative tuning is actually quite useful but if the topic is checking intonation specifically you should probably use a uke that's in tune already.
I suggest you make some sort of script or at least notes on what you want to showcase (if you haven't already) so you can focus on the points you want to go through and not forget anything.
I suggest you make some sort of script or at least notes on what you want to showcase (if you haven't already) so you can focus on the points you want to go through and not forget anything.