power supply - Can a CM choke be used to suppress common mode current in a DC circuit?

I have a setup with a DC/DC converter like in the figure below. I need to minimize common mode current on the supply input.

There are no other connections besides Vsupply + and - and Rload + and -.

I'm in doubt whether a CM choke will help reducing the CM current. And how would it need to be connected to the grounds of the DC/DC and the load. I've drawn to ways to connect it, but I'm not happy with either one.

^{simulate this circuit – Schematic created using CircuitLab} In this circuit the Supply is separated from the buck and the load with a CM choke. But because the CM choke is in the supply GND - load GND path, this increases the transfer impedance. (The choke is depicted by L1 and L2)

^{simulate this circuit} With this connection, the transfer impedance issue is solved, but now the CM choke is partly in the feedback loop.

Can I use a CM choke to reduce CM currents to the supply? How? Should I use a different filter?