Hi Ali,
The 1/4 scale will have considerably more surface detail than the 1:5.8. Given the size it easily lends itself to that. Slats will be functional, although on many real A-10's they are locked down. They were used as air diverters for the turbo fans. The flaps will be proper fowlers. The airbrakes are still being played with to check mechanical lock down. There is a continuing concern about flutter if they are functional.
Mike