I been using diaphragm howlers for a few years . I guess the familiarity from the turkey call made it very easy for me to pick it up . The open reed howlers are great but require a good bit of practice in my opinion .
I found this post too late to see and hear the video .
A good diaphragm will make all the coyote vocalizations and fine keekee's too. And like turkey hunting ,,,,hands free calling .