Depends on if it's a 7 panel test which would be a gas test..
Not so. Immunoassays, which are used for the initial screening, can be had in single panel, 5 panel, 7 panel, and up to 15 panel configs.
The Gas Chromotography/Mass Spectrometry test is only used as the confirmation test on any of the panels that have tested positive on the initial I/A screen.

What does OP stand for?
Opening post/poster

The 20 buck investment, is that what I can get from Walmart? I will head that way right now. How reliable are those?
Home tests, being assays themselves, function on the same principles as the assays used by the labs. Therefore, neither are more reliable than the other.

As far as your dilution questions go:

Creatine - Just load up enough to where you wont be making frequent bathroom trips, sitting on the toilet seat. There are no upper limits established for creatinine. As long as the creatinine level is over 20 mg/dL, its satisfactory.

Vitamins - The proper vitamin to use for urine color is B2 (Riboflavin). But keep in mind that with creatinine and specific gravity checks having become the norm in the past few years, color had become the least aspect in determining an overly diluted sample. Even samples with a nice yellow color to them can still fall below the acceptable ranges for creatinine and S/G.