Monokote dips between ribs?
John is right.
An LT-40 flies GREAT as designed. Having the ribs visible in the covering is part of its charm. ALSO, the open wing structure can give a little and bounce back, and if necessary, it's easy to repair. All good traits for a trainer.
Do the sheeted wing when you are skilled enough to stay ahead of a fast plane, and not likely to bounce it off the graound.