I was hoping for input from others as to how much creatine they've taken to successfully pass.
I am fully aware it's not going to determine how much I should take, and the only way to know is through validity test kits.
Well, If its true that youre fully aware that its not going to determine how much you should take, then whats the point in asking for others input as to how much theyve taken to successfully pass?
Youre not making any sense here.

If I've followed the steps listed by N2, and my S/G and Creatine levels read "normal", what could backfire?
The dilution technique in general if you, a longtime daily user, have a THCA concentration so high that no dilution technique can help you without overdiluting. In actuality, dilution techniques are geared more towards light/moderate users (with plenty of abstination time) rather than longtime daily users. For longtime daily users facing an employment-related U/A, subbing is the way to go if passing the U/A is important to the individual. There are many posters here who have experienced a U/A with a physical, yet still pulled off a successful sub.

I've noticed there are different kinds of drug test validity test kits available from numerous vendors.
Is there a brand that you recommend, or are they all basically the same?
I dont make any recommendations of a particular brand. I could only refer you to the Google search so you can shop and determine what brand would best suits you.