For the best reach from bed, aim for your nightstand to sit between 5 and 10...
https://lilyluxemaids.com/the-golden-ratio-of-bedside-comfort-matching-your-mattress-to-a-60-63-cm-nightstand/
For the best reach from bed, aim for your nightstand to sit between 5 and 10 centimetres below the top of your mattress