Apologies for resurrecting this ancient thread; however, has anyone figured this out?

In searching, I've found the factory tool from Mercedes (110-589-00-40-00) for as "low" as $750, while the Baum Tools equivalent is even more ($1,189).

Neither of these options are really viable.

If at all possible, I would like to avoid removing the starter to use an aftermarket flywheel lock that engages there.

Any other options? Any good sources for used tools or renting it (tried eBay but found nothing).