A downhole fluid sampling system includes a tool body to attach to a tubing string, and multiple probe pads having a curved shape and disposed circumferentially about a section of the tool body in a helical gear pattern about a central longitudinal axis of the tool body. Each probe pad includes probes on an external surface of the respective probe pad, and each probe can contact and engage a wall of a wellbore and receive a flow of formation fluid from the wall of the wellbore. An outer surface of the tool body includes multiple channels disposed circumferentially about the section of the tool body and between the probe pads. The channels direct fluid flow along the tool body.