Printed 0.3 layer height
Prints in 3 parts. I would suggest printing the brim & the ball together first in white. Then, the hat in red. Once printed, the brim should just slide onto the hat. To attach the ball to the hat, I use a small dab of super glue.
To attach to my BB-8 I used a little blu-tack / sticky tack! That should be enough to hold it in place.