Sorry it's quite confusing to write that in simple word but thanks for asking. Here's my explanation. First your guess is correct because he used TLAR and it did work. Second pertains not on your comment but for those who used TLAR in CG location on their build aircraft prior to maiden. For me this method require a lot of skills to become successful. Actually not just skills even how expert the pilot is anything could happen. However cg calculation in the example is not easily accessible due to the nature of the wings and TLAR is the most common used in estimate and it's the closest one available. In some aspect it is critical depending on the skills of the test pilot and the cost that may bring considering all safety procedure has been implemented on the test site. The problem is the non linear structure of the wings which require method to determine cg location prior to maiden in order to become successful as possible on the first flight. This pertains to the subject matter of having complex shape wing. A method that will generate function to represent wing chord for determining MAC. In other words without this, other method needs to be consider like graphical analysis, taking small increment of chord, etc. to be used in approximation rather than using integration since curve tracing is complicated although the wings can divided in portions. On our example look like the leading edge has linear portion while a semi ellipse is on the trailing edge. In addition to become more accurate such as calculating wing area for wing loading of such design may solve easily by integration IMO (because computer is available now a days). Aerodynamics is the law that governs our aircraft, airspeed is the reason why airplane stays safe in the sky. However there are hidden parts in aerodynamics which cannot be expressed in math. Those things require wind tunnel to determine. I've been in electrical and it's invisible form of energy but from small scale power plant to large scale, ohm's law is always there. From small energy cell to utilization there's always simple calculation available if we could only know it's accurate and easy.