James,
I used Mobil 1 4T 10W-40 full synthetic and performed my own oil change at 900 kms. Currently have 9000kms on the oil and the bike still shifts smoothly with no indication of oil degredation. Triumph recommends changing every 16,000 kms or yearly.
As GP stated in the previous post, as long as the oil meets Triumph's specs, there should be no issue. You might notice that some oils will cause smoother shifts, less clunking, quieter valve train operation. When you find one that works, stick with it!
For Ontario, stick with a 10W-40 weight.