Sorry, been away...
I think painting the inside looks the best, however due to the damage done to the outside when the previous bike went down the road (not mine, the one the screen belonged to) I am going to need to do some sanding which will wreck the appearance of the screen. So sand, fill and paint the outside with semi-gloss - it should work a treat
FYI - have been on a coupla short city rides, tomorrow an extended 300 km ride. From what I can see already the smaller screen allows a lot more air in (great for our summers), a lot less buffeting at the lower speeds - we'll see how that works at higher speeds. The chest from the top of my breastbone down is protected - above is in the airflow. Nice and cooooool!