I checked R1V2 bridle and find out it quite clever design. Upper two levels for each rib have same lenght in A, B and C. Primary bridle is very short, like it should be.
This means there is not a lot of room for line lenght errors in primaries, so main concern is long upper two levels. Since these have equal lenght by ribs, just comparing them to each other tell how the tune is. Fix is to stretch them equal. Absolute lenght is not very critical, but of course could be measured. Very probably A's are not shrinked - if they were like the others there wouldn't be out of tune problems.
For the symmetry I would first check/stretch A's in pairs from both sides of the kite and then do B and C rib by rib.
Finally brakes should be checked/adjusted. They have different configuration so they must be done independently or adjusted by feel/checking how much bar movement has effect.