Electrical engineering schematic and parts list

I am looking for someone to help me to build a magnetometer (more specifically, the electrical components and sensors of the magnetometer array). I am looking for high sensitivity and building an array of sensors that will work through one (or multiple) usb connections to a laptop. I can handle the software side with my team's expertise (or we could discuss you doing that too), but I am primarily interested in a parts list and schematic for a functioning magnetometer array to detect large ferrous targets from a maximum distance (identifying disturbances to background magnetism). Ideally, I am looking to establish some directionality of a target using an array of sensors and have some ability to monitor (live and recorded) sensor readings via usb connection on a laptop. I will build the housing for the magnetometer, but I want expertise in getting the right sensors and getting them wired correctly so that this device can work to locate ferrous targets from various ranges (the longer the better, generally). There are some commercial solutions available on the market, but they are all very expensive and it seems like something that could be made, so I am exploring that. If you think you could develop a parts list and wiring diagram for building a sensitive magnetometer array and consult on what are some of the physical and electrical solutions that may need to be employed, I would welcome your bid/participation in this project. Let me know your experience in similar projects and how long it might take once we have a mutual understanding of the scope.