Some test prints for getting your dual extruder into shape.
The most difficult is the Ball in box, I have included support for the ball already (so don't print with support).
I created these to test out a new way of using wipe towers for dual extrusion, you use 3 wipe towers and move the head to the wipe tower while the temperatures change from active to standby.
I've published a video at https://www.youtube.com/watch?v=3VuiOP-XwYI, I know it looks like your looking at a static image but be patient.