Beautiful job on the adaptive family.
I would vote for the nested generic model family for the arms.
And since the arm curves in TWO directions, I would break it up into two, since (to the best of my knowledge) Revit only allows curves in one direction, and then nest them into the chair.
As a matter of fact, nesting separate parts of the chair would be so much easier to constrain and restrain.
Make sure to constrain the sketch of the sweeps with parameters and associate them appropriately in the host family.
Good luck!
Rina Sahay
Autodesk Expert Elite
Revit Architecture Certified Professional
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