Given vectors $\vec { \text{u} } = \langle - 3,2 \rangle$ and $\vec { \text{v} } = \langle 4 , - 1 \rangle$, if $\vec { \text{w} } = 2 \vec { \text{u} } - 3 \vec { \text{v} }$, what is $|| \vec { \text{w} } ||$?