I struggled for AGES with alternate picking due to me being self taught and I'd developed the bad habit of down picking everything. Don't ask why, it just felt natural to me I guess. Couldn't for the life of me get the hang of picking up and down for weeks so eventually I stopped trying. Fast forward till about a week ago, I was running through some scales, improvising to some backing tracks and at first I didn't realise what I was doing but I eventually realised that I was Alternate Picking!!! And pretty fluently might I add. It's improved my playing Sevenfold (sorry for the bad pun). It sounds so much cooler and it actually sounds like I'm playing rock now. Lol. My rhythm seems better too. So I guess what I'm trying to say is, it will come to you eventually. Some people get it easier than others but it will come to you. That's the only thing I'm probably educated enough to give my advice on when it comes to this lesson. Just stick with it. It could happen to you like me and you don't even realise you're doing it.
Great lesson as always by the way!!!