Hey Jim, my pleasure! I'm glad you enjoyed it.
I too, have had the tensioner come undone, but I've just measured from the end of the sail to the tip of the spine at 3.5cm, it's a 'my setting' but it's what I was using in the video I shot.
With regards to the bridle, Bell's early examples of the Aerobe came with multiple knots on the upper leg, in discussion with Bell it was explained that the need for multiple settings was not necessary as the kite was doing well flying off the 'default mark'. I have an early version so I have the 4 'settings'. I've had a go on the others but I think Bell was pretty much on the money with the default mark...
But... if you want to play....
Mark 1: 130mm
Mark 2: 210mm
Mark 3: 240mm
Mark 4: 270mm