we adopt a constant  (by adjusting ) for all models, we might ignore the fact that at low metallicity such relatively cool stars may not actually exist.

In this study, we opt to keep  constant for both the WN and WC stars. We find that although the predicted mass-loss rates for Galactic metal content are of order $10^{-5}$ , this does not lead to the formation of a truly extended optically thick wind. Therefore, in our computations the effective temperature will not increase strongly if we lower the metal abundance. We do not claim that the effective stellar radius is not affected by a change in metal content in real WR stars; it merely reflects the fact that an adjustment of the star in the sub-photospheric region due to a change in $Z$ is not treated in our models.

The WN and WC model parameters
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For our typical WN star, we choose the following stellar parameters (see Table \[t\_params\]):  = 40000 K, and  = 5.62. The stellar mass of Wolf-Rayet stars cannot be obtained from spectral synthesis modelling, and we have therefore adopted a value of $M$ = 20 based on the compilation of Nugis & Lamers (2000) for 