Default Margins

Hi, We are finding that the default margins of 20px all around to be too much, specifically on the top and bottom. This forum pointed me to " Tools > Global Settings > Defaults > Margins/Padding" but I see nothing like that on my server.

Another post recommended adding a filters to my function.php to change new pages to have a small default but that didn’t seem to work. Below is the code I added to functions.php, started a new file, but the defaults remained.

function my_builder_register_settings_form( $form, $id ) {
    if ( 'module_advanced' == $id ) {
        $form['sections']['margins']['fields']['margin_left']['default'] = 0;
        $form['sections']['margins']['fields']['margin_right']['default'] = 0;
        $form['sections']['margins']['fields']['margin_top']['default'] = 0;
        $form['sections']['margins']['fields']['margin_bottom']['default'] = 0;
    }
    return $form; // Must be returned!
}
add_filter( 'fl_builder_register_settings_form', 'my_builder_register_settings_form' , 10, 2);