I just used your cast-on on a hat, and it's great. I see you've added a note about 3:20. You have to figure how long a viewer wants to sit to see a technique. If they're too long, you lose your audience. On the other hand, if it's long because it's repeating the steps, then it's valuable.
Re: keeping comments--sometimes the comments are rude or obscene. If you get only constructive ones, you're lucky. There's a wonderful knitter named Alison, and the comments under one of her videos are really disgusting.