In the afternoon work session my brother Bernie and I began formulating how to mount the EFIS magnetometer. First we check the aircraft for level then compare the EFIS display for level. They checked out to 0.1 degrees within each other. The magnetometer installation angles must match the EFIS installation angles and be in a magnetic disturbance free area. We decided that and after fueslage bulkhead was suitable so we fabricated a magnetometer support bracket, aligned the lateral level of the brackets and drilled them to the bulkhead then called it quits for the day.