Unless a move to synthetic is in your plans stick to 20/50.  Although cold
starts are a concern my opinion is that w/b are not happy with anything less
when they reach operating temps. The fact you are in the cold is only
relevant for maybe 5 minutes.  A block heater(preferably re-circulating) or
a pre-oilier  is your best defense.  This is my opinion based on the
happiness off my  1.9 with 350,000 km's, others may display higher oil
pressure at op. temps. Jim, north of the 49th. Others?