I may be off here, but have you checked the fluid level in the power steering? Have you checked for the belt slipping?
Try keeping RPMs high and turning through the same maneuver that gave the notchy feeling. That would eliminate belt slipping due to stretch or weak spring on idler pulley.
The strut bearing can be felt by turning the wheel while stationary and having someone touch the spring on that side. If the wheels are on leaves, dirt, gravel they turn easier than on blacktop. But you can feel the bearing catch and then let go. Mine on 2003 made a deep "sprung" sound occasionally. I thought I had a dry ball joint already.
Dual auto air on both