thats just silly talk- the "main wings " (as opposed to the little wings on the back end?) will try to assume the position THEY want which gives lift equal to the task- To clarify - you can have wash in/ wash out - set the wing at what ever angle of attack you like - BUT to fly along in level unaccelerated flight - the ENTIRE wing will assume a position (AOA) equal to that task.
The model will climb or dive till power and the drag get equalized. The entire wing will be contributing BOTH
The reason most warbirds have washout - -in models is simply to follow a scale look -
also most "warbirds" have high wing loadings and in the model - all of the wash in is just hogwash - to resolve the problem of "tip stall) what ever that is - you either must increase speed or reduce weight - no other options
You can't reshape a given area and increase lift- --you CAN make the wing more controllable at a given speed - but thats it.
Flaps do that too The lift does not increase (tho drag does) but the descent angle is more controllable.
The comment by Tall Paul is of course correct - Add inboard flap - the entire wing (and airframe) assumes a new angle - You can't do one with out the other