Note 1: how thick do you like your custard?
I don't like my custard too thick and gelatinous. Following my instructions you will have a custard that is still a little runny and not set like a soft jelly. If you want a thicker custard just heat for a little longer until you've got your desired consistency. Don't forget to stir regularly to stop it sticking to the bottom of your pan or going lumpy.