The Great Plains Christen Eagle II is also close to being a 1/3-scale (28.7%). It's actually slight larger than yours. With a 66" top wing yours is actually 27.6% scale. The GP CE has the following stats:

Scale: 28.7%
Length: 62.5 in [1585mm]
Wingspan: Top: 68.5 in [1740mm],
Bottom: 64.5 in [1640mm]
Combined Wing Area: 1436 sq in [92.6 dm2]
Weight: 16.5 - 18 lbs [6800 - 8160 g]
Wing Loading: 26 - 29 oz/sq ft [79 - 88 g/dm2]

According to the GP instruction manual, these are the recommended throws:

ELEVATOR(High Rate):1-7/8" [48mm], 1-5/8" [41mm] down
ELEVATOR(Low Rate):1-3/8" [35mm] up, 1" [25mm] down
RUDDER(High Rate):2-1/2" [64mm] right, 2-1/2" [64mm] left
RUDDER(Low Rate):1-1/2" [38mm] right, 1-1/2" [38mm] left
AILERONS(High Rate): 1-1/8" [29mm] up, 1-1/8" [29mm] down
AILERONS(Low Rate): 5/8" [16mm] up, 5/8" [16mm] down

BTW, according to the Cavanaugh Flight Museum, these are the full-scale stats:

ENGINE: Lycoming AEIO-360-A 1 D 200 h.p.
WING SPAN: 19 feet,11 inches
LENGTH: 18 feet, 6 inches
HEIGHT: 6 feet, 6 inches
WEIGHT (EMPTY): 1,050 pounds
CREW: 2
MANUFACTURED BY: Aviat Aviation
TOTAL EAGLE IIs BUILT: Approximately 1,000
FIRST EAGLE II BUILT: 1977
MUSEUM'S EAGLE II COMPLETED: 1997
MAXIMUM SPEED: 184 mph
RANGE: 350 miles
SERVICE CEILING: 25,000 feet