NavList:

The ball head on the tripod gives vertical support not possible when the Abney is handheld. I discovered a better technique with the latter shots. I would adjust the tension on the ball head to allow it to hold the Abney, but allow it to be moved with hand pressure. I then move it to first get the LL of the Sun onto the centerline crosshair. Then with my other hand, I swing the protractor to get the bubble to line up with the crosshair. Since the sun is moving, and there is a little give in the setup, I can apply a little hand pressure to tweak the sun to the centerline while making final adjustment on the protractor.

There is also an anamoly with the shape of the bubble, which I would describe as an unsymmetrical ellipse. The radius of the top half of the bubble differs from the lower half so I cannot reliably set the bubble with equal areas above and below the crosshair. In other words if a N,S,E,W orientation is superimposed on the bubble, the upper,  northern "hemisphere" is squashed down more than the southern and this changes as the vertical angle is increased. I have found it better to place the  tangent point, the E tangent, on the centerline and read the angle, I can read the tangent point more precisely. 

This is all just academic amusement. Once I get the index error zeroed in, and take enough shots, I suspect I might be able to establish a fix within 25 miles of my true location on land.