Incrementally trim the leading edge of the lower cowl until it matches the upper at the wing root. Most other places it does not match at all! The angle is awkward also, the spring clamps keep shooting off until I hot glue some sticks to the trailing edge.
The cowling halves match fairly well at the wing root, the outer edge of the exhaust holes and at the aft part line. Elsewhere the mis-match is up to 1/2". Just shitful. Hack great holes in the lower cowl in the offending areas, and it suddenly looks much better!