Curtis, you are right that a bad performer should strive to get better. I just don't think posting mini web-tv shows on YouChoob is the best way to go.
It seems obvious that you are looking to build the brand 'magicofcurtis' - the videos are shot as a presentation in the style of several recent TV shows. The T-Shirt with a huge YouChoob logo and your channel name is a bit of a giveaway. Perhaps one analogy would be if I were to post a video of my terrible piano playing in a concert setting. There's no way I am ready for that.
The most dangerous thing is to believe one's own press. I can see how it would be hard, after getting a bunch of 'Wow, that's soo l33t' comments from your peers and target group, not to get the same from the members of this board. Many years ago I got a review in a paper that said I was a fantastic magician, at least six or seven years before I deserved it. I believed it, and became insufferably arrogant (and some would say I've not really got over that...) Being self critical is very hard - which is in some way why we ask for validation on the interwebs. No one here has a reason to cut you down - but I think we do have a desire to make bad magic better and if that means pointing out the bad, so be it.
As for the efficacy of teaching - I have over 27 years of teaching experience. The advice I gave you did have information on how to improve, but it wasn't in plain sight (I thought, given your proficiency with the piano, that you were an educated and probably quite intelligent person and would be able to read between the lines. Apparantly I was mistaken). So, for your benfit, here is something a bit more explicit;
Look back over all the video you have of yourself (unedited) and examine how you handle single cards, and how you handle multiple cards. Write down all the differences, be they the grip, the tension, the body position and relative positions of the hands. Making two columns might help here. Spend ten minutes looking over that list, and for each point ask yourself why that difference is there. What are you doing differently in each case?
Now, spend a few minutes handling a single card, passing it from hand to hand, placing it on and off the deck, turning it this way and that. Video this, and watch it back. Now, do the same with a double card. Video this and then compare the two. Make another list of differences. Read through these and ask yourself, again, what you are doing differently and why.
Now you have to realise that to a spectator, during a double turnover, you are simply turning over one card. This is an action so simple that my kids were doing it when they were three years old. There is _no_ reason for there to be any other movement than turning over a card - rather than make your singles look as cramped and tense as your doubles, work to make your doubles as loose and fluid as your singles. Video your practice sessions and watch them back.
Finally, remember that during this innocuous action of turning the card, there is no need _at all_ to look at the deck. If, as you say, you have been studying Slydini you will have a good understanding of the concept of (the oft misnamed) misdirection (direction of attention is more accurate). You might want to track down Andrew Galloway's books on Ramsey for a more complete lesson. A basic choreography for a false lift might be; look at the spectator as you talk. During this action you turn over the double. Look down at the deck, calling attention to the card - the spectator will look down as well. Look back up, and when the spectator looks up at you, turn over the double and continue.
You can practice this easily using just a single turnover - you need to be able to direct the attention using your eyes and voice. Once you are comfortable with that, you can drop in the doubles and start to perform. Think of it as a piano etude and you'll have the right idea. Roberto Giobbi wrote about a card kata that he uses in a Genii column a while back - you can probably find the reference on the Magicpedia and order the back issue from Richard.
Finally, as to the question of performing in different situations; given your age and some of your comments above it seems that you are heavily influenced by David Blaine. This is not neccessarily a bad thing, but he was fresh fifteen years ago. Find another outlet and be yourself. But there is much work to do first.
Hope that helps,