At that level of aircraft you're not going to find a traditional DPE. It'll either be a Fed, an Aircrew Designated Examiner who can only give checkrides as part of an airline training program or a Training Center Evaluator who can only give checkrides for the 142 school he works for.
In addition 61.157 (b) says in order to add a type rating on an ATP or to get an ATP in an aircraft that requires a type you would have to present a record of ground and flight training. The days of just passing a checkride for a type went away about 15 years ago.