Instead of making tries or educated guesses in order to make the game more balanced, why not using the "pie rule" ? It has the great advantage of getting rid of the burden of finding the fair opening conditions and passing this burden to the players.
Here is how it works (in the case of a game with an advantage to Black) : Player A (White) plays his first move, Player B (Black) plays his first move, and then Player A has the right to choose between playing on normally or reversing the colours. In the latter case, Player B takes White, starting from the same position.
The effect is that Black has to find the first move that doesn't give too much of an advantage to either player. The slightly annoying side effect is that White will try to find a first move after which all responses lead to an unbalanced position.