I keep planning to do the written, just for the knowledge, but it'd be a shame not to use it. Though authorisation to take the written seems overkill...
To verify that you meet the experience requirements of 14 CFR part 63, section 63.37, it is necessary to obtain a written statement and signature from one of the following authorized persons: • A qualified flight engineer with the appropriate class rating • A U.S. Armed Forces flight engineer instructor for the same class of airplane • A flight engineer instructor associated with 14 CFR part 121 training program • An FAA Aviation Safety Inspector (operations/airworthiness) 1 The endorser must include a statement that they have personally verified that you meet the experience requirements of 14 CFR part 63, section 63.37. They must also identify their position, such as flight engineer certificate number, name of the training facility, and FAA inspector’s office identification.