IMHO you need to separate front and rear line otherwise you will never find a point where A & Z marker align.
Please see video below, its in german but you can figure out, guy is showing how line A and Z changes angle of attack of whole wing. Without A & Z being same spot adjusting B & C is pointless because airfoil of kite is wrong
Of course A and Z must be on the same level, there are different methods to do this with the Mixer Test and Long- or even Flull Mixer Test
The often repeated point, to have the fix points 10 cm apart for an accurate measurement ( like in flying mode) is wrong.
Indeed it is part of some methods, like this one
or for the LMT
My previous posts describes a method to level out A and a shortened Z with a pigtail, to use the " Full Mixer Test" on Soul and Sonic3.
For this method one fix point of A and Z Main is needed.