I have never looked in to the role of neurotransmitters in dreams. So I don't know what role tryptophan would play.
One thing though that helps with dreaming though is a sleep pillow containing mugwort. It helps to give you very colorful vivid dreams. Some people also add aged hops and rose petals. But mugwort is the real dream enhancer.
Yep, all sorts of things come up including instructional videos: