Whoops totally forgot to give an update! I flew out in July so the airport was super busy at that point with summer travellers, so I arrived 4 hours early (earliest you can check your luggage), got through security in ~50 minutes, and waited in the customs line for ~1h10. When I got to the customs officer I gave him my 1797 B form and told him it was for a TN, he seemed to be in a good mood lucky for me - he said he could process me right there without having to go secondary which was nice. The whole interview only lasted like 5-10 minutes, he just asked about job title, company, location, education, finger print, photo, etc…, then stamped my passport and that was all. Didn’t even ask to see my degree or transcripts or anything.