Hi Andy,
The maximum number for this trip is 33.
The Canada eTA program is fairly new, and consequently definitive processing times are not yet available from the Government. Most Canada eTA applications are processed in a few minutes. If your eTA Canada application is not approved within a few minutes, it likely requires further processing and you can expect to receive an email from Immigration, Refugees and Citizenship Canada (IRCC) within 72 hours containing additional instructions. There is no exact timetable for how long an eTA takes before it is approved or declined, but the standard Canada eTA processing time in such situations is 72 hours.
Thanks,
Vickie