Very cool and thanks for posting. This is exactly one of the items on my to-do for this year, but as a zombie and with less reach. I like how you anchored the cloth for the feet to the chair cause I was struggling with what to do about the lower body.
Before changing out the air cylinder try using a flow control on the return it will let you adjust the flow of the air going out of the valve on the return and slow it down. Maybe you're using one but from the looks of the video I'm guess you're not...if not it will fix your problem
Awesome prop! The quick return is actually more scary as far as I can see, but I can understand if it's tough on the mechanism. Anyway, the effect's great - I like the eyes, too. Glowing eyes can look cheesy, but these work well with the prop.
Though I have to say, before I watched the video I was expecting zombie Elvis .
I am going to build "The Castle Grey Skull " well at least the face out of foam . I think out of foam. Google it. It was a kids toy from the 80's. I also thought of using a foam skeletal structure and covering it with wire window screen and Monster Mud. Oh ya did I mention that it was going to be 8 1/2 feet wide and 14 feet tall. It will also be made in five different sections. Any thoughts you would have would be greatly appreciated.