Ronald Vermeij

Blender - UVmapping - (Unwrap or SmartUV Project) - Non symetrical uv-maps-sections

I currently modeling the General Dynamics YF-16 (the mother of all F-16 on the planet).
After a long journey I have arrived at the UV-Mapping , Unwrapping and texturing section of this project.

My current challenge: Bended / Deformed UV-Map sections
When I use the
- [UnWrap] method or
- [Smart UV Project] method, 
sometimes a portion of my UV-maps does not get unwrapped 100% symmetrically.
You can see an example of this below (the section with the red line in the middle)

QUESTIONS - about the [UNWRAP] method:
1 - Can one influence the result of the [UnWrap] operation (yes/no)?
 with something else then placing seams inside the 3D-mesh?

2 - What (internal) factors does Blender use to group islands-of-vertices together?
Is this only based on the seam-locations or are there other factors at play here?

QUESTION about the [Smart UV Project] method:
3 - Which Angle (between what?) is being used to in the [Angle limit] field

I've already read the Blender manual section on this, but it doesn not provide much answers / details
on how Blender actually does the trick.
- https://docs.blender.org/manual/en/dev/editors/uv_image/uv/index.html

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