Now I'm wishing I had a 100' grain bin and a pulley!
Just think, if the tow hook is in the usual location, the plane would be "past vertical" until it got close to 100' high. Only then would the string be parallel to the ground and the plane in a "normal" launch attitude. You probably wouldn't want to come off the line until you were well past 100', otherwise it would be like a pop off on a regular launch. Hopefully you get there before it get's pulled through the turnaround pulley.