What I am recommending, since it might seem confusing (it can seem a little overwhelming)....
Sour, Bitter and Umami should not be your focus in your rub. So start with a balance on Sweet and Salty. Add in the flavor profile stuff you are shooting for, like chiles, onion, garlic, etc, one at a time, and in small amounts until you feel your sweet/salty balance is broken. At that point you know how much of the other stuff you can add to maintain balance.
For example, start with Paprika. Once you have your Sweet/Salty ratio, add some Paprika a bit at a time until you think you have passed the point where it makes things better. Use that as a guide going forward, but now add in a little Garlic in place of some of the Parpika until you find the right blend of Parika/Garlic you want added to your Sweet/Salty. Repeat with other flavors.
Once you have the Sweet/Salty and your flavor profiles where you are happy, then it is time to tickle the tastebuds by engaging in the other basic flavors. See if adding a little touch of sour makes it seem to jump more on your tongue, and how much you can add before you start thinking the Sour is too prominent. Do the same with the Umami and Bitter flavors.
Hope this helps. It will take time. You will probably settle on a rub, then make soemthing different several months later, and so forth until maybe, just maybe, you find a rub you stick with.