Best Time to Sell Belts?

I have sold one Purple Witch Belt during this event and I've been making more to sell after the event. How long should I wait to sell my belts once the event ends? I know there will be another belt release with the Pyramid PQ, so I should probably sell them before that comes. What time would be best to make the most profit off these belts?

Thanks

The moment NPQ is spotted in GMS data.

NPQ belts are already in our data AFAIK.