Nice!I figured that if I went equal parts, the salt would overpower everything else. Suspicion confirmed. Now to Winco for the parts
While at Winco I think they have the big 1 pound shakers too if you wanted to make up a big shaker of it!
Also I use granulated garlic and I use dehydrated/minced onion because for the longest time, that was the only kind of onion seasoning my Costco would sell. I fell in love using it instead of other onion options (granulated would be my next option, onion powder gets too clumpy for me).
Also, since you like SPOG it is easy to go ahead and get you some paprika and make an SPOG + Paprika. This is great for chicken and pork and is my go to for those meats, though it will work on anything. I used to just do SPOG and then shake on the Paprika individually but got tired of using up my straight SPOG so much so I just mixed up an SPOG + Paprkia.
Finally, I also do not mind doing 2x black pepper. I have and will do on a whim but I also buy really really good black pepper and it is so fresh and good that it actually makes things a little spicy, and I'm not a person that is sensitive to spice, like bring on spicy pepper food for me. BUT even I noticed that at 1 part of my good black pepper, it would have enough kick to it that sometimes people thought I was putting some kind of heat in the seasoning and I was doing no such thing. Even I noticed it hahaha. So your milage may vary on how much black pepper you want to go with, and may depend on how good and fresh and how much kick is in your black pepper :D