The Jerk seasoning quantity is a small amount of 2 Tablespoons. You can double that anytime to prepare more of the jerk seasoning. I find that 2 tablespoons is enough for a hot spicy chicken rub. Otherwise, I just prefer to prepare a new batch whenever I need it since the jerk spice blend has deeper flavors with a fresh batch of spices.
You have two options to prepare the dry Caribbean jerk seasoning/rub.
For more Jerk seasoning flavor : use whole spices, toast them on a dry pan until you can smell the spices, let cool and then crush to a fine powder in the mortar or grind with an electric grinder. Mix all the spices together.
For a quick 5-minute Jerk Seasoning: use ready-made spices in powdered form and mix all the ingredients together.