Switch between multipage and horizontal tabs?

It looks like part of the problem is that user_register_form() and user_profile_form() both use user_account_form() which Field_Group has taken over.

What I did:

function mymodule_form_alter(&$form, &$form_state, $form_id) {
  switch ($form_id) {
    // Create a new account form.
    case 'user_register_form':
      // We sort of need to cheat.
      // We will override the multitab settings to become multipage.
      foreach ($form['#groups'] as $group_name => $stuff) {
        if ($group_name == 'group_tabs') {
          $form['#fieldgroups']['group_tabs']->format_type = 'multipage-group';
          $form['#fieldgroups']['group_tabs']->format_settings = array(
            'formatter' => '',
            'instance_settings' => array(
              'classes' => '',
              'page_header' => 1,
              'move_additional' => 1,
              'page_counter' => 1,
              'move_button' => 1,
              ),
            );
        }
        else {
          $groups[$group_name] = $stuff->label;
          $form['#fieldgroups'][$group_name]->format_type = 'multipage';
          $form['#fieldgroups'][$group_name]->format_settings = array(
            'formatter' => 'no-start',
            'instance_settings' => array(
              'description' => '',
              'classes' => '',
              'required_fields' => 1,
              ),
            );
        }
      }
      break;