Change header slider depth

I must be missing something. I want to make the slider deeper (from 500 to 800px), and have been reading the documentation about filters. I have added this to my child theme’s functions.php – is this correct and if so what else do I need to do as it has not made any difference?

<?php

add_filter( 'tc_slider_size', 'my_slider_size');
function my_slider_size() {
    $sizeinfo = array( 'width' => 1170 , 'height' => 800, 'crop' => true );
    return $sizeinfo;
}

add_filter( 'tc_slider_full_size', 'my_slider_full_size');
function my_slider_full_size() {
    $sizeinfo = array( 'width' => 99999 , 'height' => 800, 'crop' => true );
    return $sizeinfo;
}