Release cycles and deployment windows determine when the assignment can usefully start, and the employment history abroad determines whether the case can be built at all. Check the history first. Prior US work, contractor periods, or an internal transfer between group entities can affect how the qualifying period is counted.
Verify the employment record early
Engineering careers often include a stretch as a contractor, a secondment, or a move between group companies that looked administrative at the time. Assemble a simple timeline of employer entity and location for the past several years and have it reviewed before anyone plans around a start date. Then treat petition approval, any visa step, admission, and the lawful start of work as separate events with their own timing.
Add one further scheduling reality to that timeline: engineering evidence competes with delivery, and delivery usually wins. A specialist valuable enough to transfer is by definition busy, and the hours needed to describe their knowledge come out of the same week as a release. So put the contributors' time into the plan the way any other commitment is planned — named people, agreed hours, protected in the schedule — rather than assuming it will be found.
Then treat the qualifying history check as the item that runs first, since it concerns dates already fixed and can end or reshape everything behind it. Hypothetical example: a video codec integration specialist's employer books two half-days with the principal engineer four weeks ahead, and those four hours produce better material than the twelve that would otherwise have been taken in fragments between other work.