Fieldset Text Defaults

Thanks. I see WP has filters for default content and some others, but not for meta. 🙁 A bit hacky, but I got the desired result with some JS:

add_action( 'admin_footer', function() {
?>
    <script>jQuery(function($){
        var $input1 = $('.post-new-php.post-type-staff_testimonial input[name="attributes[0][heading]"]');
        if(!$input1.length) return;
        var $clone1 = $input1.closest('.rwmb-clone');
        $clone1.siblings('.add-clone').click().click();
        var $clones = $clone1.siblings('.rwmb-clone');
        $input1.val('Position');
        $clones.first().find('input[name^="attributes"]:first').val('Team Member');
        $clones.last().find('input[name^="attributes"]:first').val('Location');
    });</script>';
<?php
} );