Stupid Mac::Glue Tricks: Quick-Edit iTunes Track Properties

You can edit properties for tracks at once in iTunes, but not all of the properties are available in the UI. For my iPod shuffle, I like to have audiobooks and podcasts, some of which do not already have "Remember playback position" and "Skip when shuffling" set, as I'd like them to be. And I cannot see a way to modify those in the UI in bulk. Therefore, I select the files I want to edit, and:

use Mac::Glue;
my $itunes = new Mac::Glue 'iTunes';
my $sel = $itunes->prop('selection');
$sel->prop('bookmarka ble')->set(to => 1);
$sel->prop('shufflable')->set(to => 0);