From my point of view, Your bird (nice kite!) needs another wing-strengthening structure:
2 dehidral carbon
tube-rods (at Your bird's wingspan: 6mm diameter
) instead of gf-rods (too weak, too heavy), and tensioning battens across the 2 main rods (3mm carbon, massive), at the last third of a winghalf.
This helps to avoid wrinkles within the wing, and twisting during flight, as well as what I call 'counter steering moments', what means:
When You are sure that You have steered to the right, the bird follows for short, and then - due to the unwanted flexibility and twisting of the 1-rod-wing construction- the bird makes unwanted moves in other directions.
When a single-liner birdkite is hanging at it's string, this does'nt matter - wing fluttering looks nice then, and the string stabilizes.
For effective RC-purpose, a stiffer wing of vectorized single-liner bird-kites is a must.
The photo shows the improvements I made at my Eagle (similar constructed single-liner kite like Yours), with the result of much more flight stability (see the videos).