I usually cut my wickerbill completely gone when I race indoors, especially when there's a lot of 180's. The bigger the wickerbill, the more the car will stall out in the middle of a turn. The lower one will rotate nicely around turns and give plenty of downforce.

Just make sure you use a dremmel with a sanding wheel to get the corners of the wing. That will help prevent cracking by not having any sharp angles.