I think you'll find Bump Steer is a bit different not caused by Castor but due to the Pan Hard Rod not being Exactly parallel to the Drag Link, That shouldn't be a problem with a Stocker.
I have heard that Jeep are aware there is to little Castor in brand new cars but you can always get adjustable Control Arms.
I wonder if it IS due to the Front Axel and Front Drive Shaft being driven all the time? i have Free Wheeling Hubs installed so maybe i'll never experience DW.
Hope Not