Enforce Minimum Length by adding spaces
In template file for your field you can use good old PHP sprintf:

$right = sprintf("[%10s]\n",    $s); // right-justification with spaces
$left  = sprintf("[%-10s]\n",   $s); // left-justification with spaces

$right === "    monkey";
$left  === "monkey    ";


In your case
    &lt;?php print $output; ?&gt;

should turn into:

 &lt;?php printf("[%10s]", $output); /* if you want spaces before string */?&gt;