Obtaining 1:1 Ratio for Botox?

It is my guess that you are referring to 1 unit per .01cc. This is accomplished by adding 1.0 cc of saline to the vial of botox containing 100 units.

Botox comes as a white powder at the bottom of the vial, and this contains 100 units of Botulinum toxin, Type A. I typically reconstitute the vial with 4 cc of saline, so a 1cc syringe contains 25 units.
You should always ask your doctor how many units you're getting, since that will affect your outcome.
Where did you hear the phrase: "1:1 ratio with Botox"?
I hope this helps.

The reason for your confusion is that you are asking the wrong question. Regardless of how much saline is added, it is the number of units not the volume or dilution that matters most. Some practitioners may intentionally use confusing terms to disguise the amount they are using. Keep in mind also that units are a biological activity assay, not a weight measure.