Hi Jez,
You DO need to submit CANPASS details even for a techstop - been through there a few times recently en-route Caribbean and return (Need to do it both ways). If you don't want to upset them too much let them know if your ETA changes by more than 30 mins. Easy enough to do it the day before as long as you have all the info and then just a quick ammend all if reqd on the day - usually they will only accept the call from the Captain. Number is +18882267277 (toll free in USA from landline) Dont forget to get your "Clearance number" from them when you call on arrival - the lovely Cathy will need it and it is worth holding onto with your paperwork after "just in case" (never needed it after the event yet though!!).
Cheers and have fun SF
