To create the sweep for flamenco arms, grow wings! Spread your back wide and lift your arms. Keep this image of wings...feel like you back body is wider than your front body.
The arms must have energy all the way to the fingers, use Dynamic Tension. Feel your arm is moving with the strength of the shoulder muscles
Feel your arm pits are deep caverns with vaulted ceilings.
In the passage of the arm, you must go through all the "stopping" points and create the shape necessary at that point (ie Never just bring your arm up with out passing through: low "v" to "t" position to high "v" etc...). In low "v" & 6 o'clock, make sure you do not compress the arm pits. As the arms raise, do not lift your shoulders. Elbows must remain high throughout as the shoulders must remain down.