I don’t recall Red Line Power Sport having 20w50. 20w60 is available, and there’s no problem mixing one Power Sport viscosity with another. Red Line does have 20w50 in their automotive lineup. It wouldn’t cause a disaster if you topped off with a small amount, I would stick with the Power Sport if possible. The 10w50 Power Sport is also available and one of the very best oils money can buy. Your ambient temperature is the determining factor for your choice of viscosity. Over 90F, and 20w60 is preferable.