The Great Circle track between any two given points of equal latitude will produce a true heading of either East or West at the mid longditude. If you were to travel between N60.00.00 W10.00.00 and N60.00.00 W50.00.00, you would cross W30.00.00 on a true heading of 270 degrees True (the apogee of the great circle track). The displacement of track from the N60 Latitude would be proportional to the Sine of the Change of Longditude. The Sine of 60 degrees is 0.5; therefore, the Convergency is 30 degrees. The Initial True Track is half the convergency = 285 degrees. The final True track into N60.00.00 W50.00.00 would be 255 degrees.
If you were to include any other waypoints between those that I've used in the above example (even if they were directly 'on track' of this particular Great Circle example), the Initial True Track (and final True Track) to any other waypont will be different to the example... therefore, the displacement (abeam) will allways be different. If you split a great circle track into segments, the initial True Track between waypoints will allways be different; because they are different Great Circles!
John