Columbia using 3000 gallon Bambi Buckets so should be able to lift the Dak quite easily when using a long-line. Downwash on such a large surface does increase the apparent weight a lot but with a 200+ foot line that should not be a problem.
Columbia also removed the external fuel tanks and replaced them with tanks inside the fuselage, improves performance due to smaller profile not obstructing the downwash as much. See pic.
