Sure those overpriced bottled diluters may brag about containing creatine. What they dont tell you (perhaps in an effort to avoid blowing a sale) is that it takes 2-3 days for the body to convert creatine into creatinine in order for it to be present in the urine. Therefore, the creatine ingrediant will do you no good when the snake oil product is consumed on the day of the U/A (in which youre required by the product instructions to do so). Any creatine-loading must be done at least 3 days before the U/A.

How much creatine you would need would depend on a few factors, including your "baseline" creatinine level and how much fluids were consumed - and youre not going to know any of this without testing your creatinine levels with a validity test kit.
You should have a few of these kits at hand anyway when utilizing dilution techniques, so you can stay on top of your creatinine levels as well as your S/G. Do a Google search for "drug adulteration test kits".

The proper vitamin for urine 'color' is B2 (Riboflavin). But it must be understood that with creatinine and S/G checks being lab SOP in recent years, color became the least aspect in determining an overdiluted urine sample. Even samples with a nice yellow color to them can still be ruled "diluted" due to unsatisfactory S/G and creatinine levels.