Sorry for answering so late. And noooo, your posts are not amateurish. I love them.
Thank you so much for searching for a video, but sadly the wide elastic hack does not work with my jeans problem. I will perhaps make 'problem' photos one day :-D
Most of the videos only show how to alter the waistband, but my problems area is also more in direction of my bum (no idea how to name this nicely in German it would be "Popo") and the gap between jeans and back is much bigger.
And with using such a big elastic, there is no possibility to use the zipper, I imagine it would not look so flat in reality as shown on the video (more over as I do not look like the woman in the video :-DDD)
And you are right, there may be already videos / tutorials for everything. But not everybody is so nice like you and we can chat about it openly (I would not do this with everyone <3)
So yes, to all your post.