Shallowest DOF: Nokton 17.5mm f/0.95 or 35mm f/1.4 on full frame?

Hi.

I currently use a 5D Mark II with a 35mm f/2.0. I'm considering buying the Sigma 35mm f/1.4 or finally making the switch to M43 and getting a 17.5mm f/0.95.

Given that the subject I want to focus on is standing at the same distance from me (and the scene is the same), which of the two options (35mm f/1.4 on FF vs 17mm f/0.95 on M43) will give me the most background separation (shallowest DOF)?