The sago to be used is the small one. I have used the big one and hence it was still not smooth.
The amount of water is totally dependent on the cooking time of sago. If the mixture sticks to the pan and the sago is still not cooked, add water in increments of 1/4 cup till the sago is completely cooked and transparent.
You can sprinkle in pistachios or even sesame seeds for a final touch.
Personally I like this dessert warm. But you can have it cold as well.