Faster than most categories, since a Canadian citizen may present the request at a port of entry with the supporting documents. The realistic constraint is usually assembling the evidence, particularly the letter identifying the supervising professional.
The paperwork, not the process, sets the start date
Hypothetical example: the employer wants the technologist on site in three weeks and assumes the border step is the obstacle. It is generally not. What takes time is getting a letter that names the supervising professional, states their qualification and describes the duties precisely enough to be matched against the listed entry, because that letter usually needs input from an engineer who is busy.
Request it immediately and review the draft before signature. If the employer prefers to file Form I-129 instead, that route has its own processing time, published by the responsible agency and subject to change, with premium processing available at additional cost. Do not resign from the Coalhurst position, give notice on housing or move the household before the status permitting the work actually exists.