Which weight VR 1?

I just put a low mile 318 in my Dart. The motor sat in a garage for 4 or 5 years its from a 75 cordoba. It will be started a few times this winter and then will be a daily driver in the summer. I can get VR 1 from NAPA in 20w 50 and 10w 30. and straight weights. Should I use the 10W 30 now and switch to 20W 50 in the summer? One of the reasons I ask is I have never used any 50 weight oil in my cars? The motor is stock with 4 barrel and dual exhaust and will not see any high RPM duty.