Confirm the continuous year abroad first, finish the product documentation and the dealer-support arrangement, then file with enough lead time for standard or premium processing plus a margin for a request for evidence. Set the assignment start after the expected approval.
The documentation takes longer than the adjudication
The one-year requirement is measured at the filing date, so read the payroll before anything else. The slowest step is usually not USCIS but the company: locating and translating the internal manuals, extracting the warranty history, and negotiating the dealer-support arrangement with the subsidiary and its dealers. Plan those tasks backward from the date the dealers need him, allow for standard processing published by USCIS or budget premium processing, and add a margin for a request for evidence about control at dealer sites.
After approval, a Canadian citizen presents the approval notice at a port of entry without a visa stamp. Record his admission date, because the five-year L-1B total runs from it and includes any earlier L time. If the assignment is expected to recur, plan the second and third years now rather than when the ceiling approaches.