I made 2 quick contracts on PC to make Jeff spawn on The Author and on The Vector, so that you have to waste as little time as possible making him respawn on said maps.
Epic: 1-16-8612704-32
Epic: 1-15-1661636-32
To make him respawn on Patient Zero Hokkaido, you have to shoot and ignite the barrel on the far right of the map (outside the compound) on The Vector. Then proceed to complete the mission however you like and exit. This will make him spawn in Hokkaido. You can identify him by using your instinct. He starts below the water tower in the junkyard, hiding in the bushes.
He starts in Jason Portman’s room in Hokkaido and will wander all around the public areas of the map.