The petition has to be prepared and adjudicated before the work begins, and no commercial urgency shortens that. What can be compressed is the internal evidence gathering, which is usually the slowest part of an L-1B file.
Compress the part you control
The parts outside the company's control are the adjudication itself and any consular step that follows. The part inside its control is assembling the material that shows what is proprietary and how this person acquired it, and that is where weeks disappear while people look for training records and old service reports. Start there on the day the assignment is proposed. In parallel, confirm the qualifying year abroad from payroll and confirm the corporate relationship from formation records, because those are quick if the records exist and expensive if they do not. Resist the temptation to send the technician on a short business trip to begin the work informally; the character of the activity, not its duration, determines whether it requires work authorisation, and an early misstep complicates the petition that follows.
Hypothetical example: A commercial-bakery equipment maker schedules a launch in three phases, but its specialized-knowledge employee completed a three-month unpaid leave during the proposed qualifying period. The first review should set out every employment date, leave category, and foreign work location before filing. Payroll and leave records settle whether the required continuous foreign year is present. Technical evidence should be collected in parallel, especially when it needs confidentiality review or translation. Do not schedule the person to operate the American production line before permission is secured. If the leave creates a timing issue, revise the transfer date based on records rather than trying to explain it away later.