Theme customizer: How do you grab the value later?

I’m working on a custom site, doing all my work in a child theme. I need to add one variable, slider speed, to the customize control system. I’ve been able to modify the custom controls via the following additions to my child-theme functions.php file:

function Primm_customize_register( $wp_customize ) {

$wp_customize->add_section( 'primm_section' , array(
    'title'     => __( 'Primm Home Page', 'Divi-child' ),
    'capability' => 'edit_theme_options',
    'description' => 'Setting options for home page'
) );

$wp_customize->add_setting(
   // ID
   'primm_slider_speed',
   // Arguments array
   array(
       'default' => '5000',
       'type' => 'option'
   )
);
$wp_customize->add_control(
    // ID
    'primm_slider_speed',
    // Arguments array
    array(
        'label' => __( 'Cycle Time on Slider (0.001 secs)', 'Divi-child' ),
        'section' => 'primm_section',
        'type' => 'text',
        // This last one must match setting ID from above
        'settings' => 'primm_slider_speed'
    )
);
}
 add_action( 'customize_register', 'Primm_customize_register' );

That stuff seems to work well. I can make changes on the admin custom menu, save the settings and see that a value seems ‘set’. On the other hand, I’m attempting to call that variable from within my home.php file.

 $slider_timing= get_theme_mod('primm_slider_speed');
 echo("Slider Timing: ".$slider_timing);  // test only
 var_dump($slider_timing);

total fail. This is my response:

 Slider Timing: bool(false)             

Been working on this for hours. I’m missing something, but its just not clear to me what. Note: my child theme is “Divi-child” (based on the directory name at root/wp-content/themes/Divi-child ) Anybody been here before on the general topic of WordPress Theme customizer? How do I allow admin users to set a value in ‘storage’ and then retrieve it again later? Many thanx, Zip.