We currently are wirebonding (aluminum wires) on a flex circuit (polyimide) using  w/ the following
5-10 microinches of immersion gold over 150-200 micro inches of Ni

We are going to an FR4 board and need to use gold wirebond.
Do I need to change the plating? I recall hearing something about adding palladium?

Wirebonding is not my strongpoint