I found that the best way to find a dummy through the night without turning the light would depend on what colour the cot/bassinett sheet was.

I found that if I used a light coloured sheet the dummy was easier to find if it was a darker colour.

(The light from the street light comming in around the curtain was enough light.)

The Glow in the dark dummies were more than double the price of the normal dummies.

My theory works quite well if baby isn't lying on it.