Thanks. I saw that one but I thought you called it something else.
The paste is convenient but much more expensive... not too bad if you are only doing it once. The tub of powder lasts a long time.
I wouldn't do tryptophan for trailering... You don't want him sleepy, you just want him relaxed. It's hard enough standing up without hands in a moving trailer, without being drunk ;~D
What's his issue? What does he do in the trailer?