Work backwards from the installations the subsidiary has committed to, and allow for a request for further evidence, which is common where customer-site work is involved. Do not promise a customer a commissioning date that depends on an undecided petition, and identify what can be done from Canada in the meantime.
Protect the customer dates you can control
Barn projects are scheduled around herds and weather, and those dates are genuinely hard. That is a reason to file early with complete evidence rather than late with pressure. Build the specialized-knowledge documentation while equipment is still being manufactured, settle the American position description in the same period, and file as soon as both are sound. In parallel, identify the work that does not require presence in the United States: modelling and layout design, factory testing before shipment, and training the subsidiary's own installers in Ontario. That reduces the number of dates that depend on a decision nobody controls, and it gives the company something honest to tell a customer if the petition takes longer than hoped.
Hypothetical example: a Tyendinaga renewable-materials producer schedules an American equipment installation around the only employee who knows its quality-control algorithm. Count the qualifying foreign employment carefully, including changes in payroll entity, unpaid gaps, and time spent outside the organization. Build the evidence collection before booking the installation. A last-minute explanation that a break was insignificant can turn a predictable timing issue into a cancelled deployment. Contemporaneous payroll and project records are much stronger than a retrospective explanation prepared only when a deadline is imminent.