Applying minox only on the hairline?

Right now i'm only applying minox to my entire hairline, and 1 or 2 cm behind it.
Would i be better off if i started applying minox to my whole head instead of just my hairline? I only have the receding hairline, the rest of my hair is still pretty thick.

But i'm not sure if 1ml would be enough if i were to do this, since 1ml is already barely enough to cover my entire hairline.