Any creatine intake needs to be done 2-3 days before the U/A. It takes 2-3 days for the body to metabolize creatine into creatinine, so the creatine in the magic potions are useless since youre instructed to ingest the potion on the day of the U/A.
Doing both the potion and the N2 Dilution method will increase the likelihood of the sample coming back "too-diluted". Some employers will accept a "too-dilute" while others may grant a retest, and others will simply move on to the next job candidate.