Photos in the Squadron Signal book show a LOT of flap for takeoff. About equal to angle of the line on the fuselage between the foot holes in the sides. 45° or more!
The flaps probably wouldn't have been used at all taking off from an airfield.
If by "manually set" you mean your flaps will be down all the time, you won't like it in flight!
One of the last photos in the book shows an F6F drone with a 2000 # bomb on a steam catapault during the Korean War. No flaps!
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Flaps were probably a necessary evil before the steam cat on a carrier.