The first four spices are essentially the same. The old bay seasoning calls for bay leaves, but you're gonna have to finely grind them or they're unpleasant to eat. Better off just tossing bay leaves in separately imo.

The way I make spice blends is to grab a series of different measuring sizes, the biggest being 1/4 c (for big batches), then 1 tbsp, 1 tsp, 1/2 tsp, and 1/4 tsp. Start with your primary flavors and use the bigger sizes, then go down.

Like the "mexican" type spice is generally mostly ancho (chile) powder, which is more like rehydrating a pepper than a seasoning and tends to be used in much higher quantities than other things. Paprika, onion, garlic are all important flavors. So is oregano, but technically you're supposed to use the milder mexican oregano. I don't see that in the stores, so most people just use regular oregano. Anyways it gets less. Cumin, red and black pepper can be overpowering so I tend to add the least of these.

The comments say not to add salt, I do but you do want to take it easy on the salt. You can always add salt, you can't take it away if you want more flavor without extra saltiness.