Whichever route applies. Designation records are usually obtainable from an active professional body, while academic records from a long-closed or restructured institution depend on archives and successor bodies whose response times cannot be predicted.
Identify the slow dependency early
If the degree route is required, start the retrieval request the same week the route is confirmed, because it is the item most dependent on others. Ask the institution or its successor what form it can issue and how it transmits records. If the designation route applies instead, the timeline is usually governed by the offer and the rest of the file rather than by document retrieval.
Institutions and professional orders set their own turnaround for issuing attestations and certified copies, and a translator needs the final document before starting. If a different listed credential route is actually available, evaluate its real evidence; do not invent one to avoid the issue. If the employer, duties or assignment changes, ask for a fresh review rather than assuming the original plan still applies. A signed offer describes intended employment; it does not by itself authorize U.S. professional services. Time the start date after whichever step is slowest, and remember that TN is granted for up to three years at a time and can be renewed while the same conditions hold.