// Disable Sideber on custom archive
add_filter('avia_layout_filter', 'avia_change_post_layout', 10, 2);
function avia_change_post_layout($layout, $post_id){
    if(is_category('CATEGORY ID/NAME HERE'))
    {
        $layout['current'] = $layout["fullsize"];
        $layout['current']['main'] = "fullsize";
    }
    return $layout;
}