If I can share a totally respecful and peaceful comment: the "manner" evoked might change everything. Steel poles + mag not only impart a higher inductance but also a lower Q factor (a wider and flatter resonant peak) + a weaker magnetic field, making a single coil tonally closer to a humbucker than to a single coil with mag poles.
Personally, I don't
know if a QP must be mounted with 500k or 250k.
Other members have already explained why it can be a good idea or not.
My own experience just makes me
think that 500k pots can be set to sound like with 250k ones: let the volume pot full up then lower the tone control for a lower resistive load and the result should be practically the same. A 500k volume becomes potentially annoying only when lowered, because it puts more resistance than a 250k between pickup and output, with the related darkening effect (but it can be corrected by a treble bleed).
Good luck in your choice, OP.