What is the best way to even out a tan?

I will use/apply a "progressive sunscreen" that reaches a top protection value depending of the exposure. The more sun received, the quicker protection developed. In that way, the different parts of the body, that receive the sun with different proportion and intensity, will equal the amount that reaches the skin and therefore the final suntan of the whole body will be even.

There are several patents ongoing and hope the product will reach the market soon.