Contours of the magnetization of the equatorial wind (σ_wind; solid lines; Equation (B3)), and of the polar jet (σ_j; dashed lines; Equation (B5)) regions of the protomagnetar outflow, in the parameter space of surface-magnetic-field strength B_P and spin period P, as estimated analytically in Appendix B and calculated assuming ﹩{L}_{{\bar{\nu }}_{e}}=6\times 1{0}^{51}﹩ erg s⁻¹ and θ_j = 20° for the size of the polar cap contributing to the polar jet. The locations of protomagnetar wind models are shown as solid points as marked. Our most strongly magnetized and rapidly spinning models achieve σ_j ≳ 20–50, showing that their jets may be capable of powering GRB emission.