You have to use the more restrictive regs therefore if you are limited to 2600 in the USA, then use that in canada, if canada allows rvr 1200-600 etc... and you are in the states where the limits are 1600 then 1600 is what you use.
clear as mud i'm sure
2) When within a foreign country, comply with the regulations relating to the flight and maneuver of aircraft there in force;