First, combine your dry ingredients. Use a fairly large amount of garlic powder. Put in about %130 of what you think might be appropriate. (But if you think any amount less than 1 1/2 tablespoons is appropriate, you are wrong. I'm sorry you had to hear it from me.)
Add the paprika. That paprika has probably been sitting there for over a year—perhaps over five—so it doesn't have any flavor. You might as well add a bunch. I'd say at least a tablespoon. More if you just want to get rid of it so you can buy some nice, fresh paprika that still has some flavor. Alternately, if you have some nice fresh paprika, a tablespoon might be a nice amount. It has some good flavor yet; why not enjoy it?
At this point, we reach the most disturbing part of any recipe: the part that involves mayo. Mayonnaise used to be an elegant, subtle, rich sauce, similar to hollandaise, except more French. Sadly, these days are long gone, and today mayo is made exclusively from recycled rubber remnants mixed with a mash of fermented plastics. Or so I am told. In order to minimize the nasty mayo flavor in the eventual sauce, I prefer to avoid Hellmann's/Best Foods' and Duke's and whatever else, and use a nice, healthier olive-oil mayonnaise. Anyway, take a deep breath and add about a cup of mayo. Mix.
Add ketchup until you get a nice subtle pinkish-peach. Maybe 1/4 cup.
Add lemon juice and soy sauce. I put in probably 2 tablespoons of each, but I make it differently every time. Sometimes I forget the soy, and don't miss it, so that might be something to do if you're watching your sodium. The lemon juice is pretty non-optional, though.
Then add the Sriracha. I put in about two tablespoons or so, but you could add less, if you are infirm, or unable to stand significant quantities of deliciousness. Be polite: If you don't call it sriracha, call it "chicken sauce." If you don't have sriracha, I suppose you could use some random "hot sauce," but I would judge you. I would say you are not committed to your food. But hey, it's your house. You can go ahead and mess this whole thing up if you want.