The outermost layer of the communication onion would ... focus on benefits ... A second layer for a specialist audience could include a more detailed elaboration of the risks.

Since the specialist audience also reads the general-public materials this would open you to accusations of being two-faced (or even hypocrisy).

I am also not clear on the specific goals of this exercise. Do you aim to manipulate the public opinion (that's a craft with its own set of skills and many tricks of the trade)?