Here's the tutorial I used to make the wefts. I found the hairs got caught up in my machine if I went too fast, also I was using a twin needle which has always been temperamental in my experience. I switched to a single needle for the second weft, and used some paper underneath to keep the hairs away from the inner workings of my machine and it worked a lot better than the first time. The paper tears away super easily once you're done sewing!
I also found that since I was using synthetic hairs, they didn't really stick to the tape well at all. The paper beneath the wefts while sewing helped on that front too. There is water soluble fabric you can get for such applications, which I think I'd want to get for the next time I need to do this.
A really great tutorial though! Helped me a lot, I had no idea what I was doing lol, how do wig?