Oddly enough a Tupperware bowl works great. If you have the cutting tools a Stainless salad bowl is another cool choice.
The key is to make a metal backing ring (stainless/aluminum), and install the bolts/machine screws from the fan side, and Nylok nuts on the outside w/ decent size flat washers. I used the rim off of a stainless bowl for that ring, and 4 number eight Carriage bolts. Areomyst gave me the scoop. I just cut the center strut out of it, along w/ all the factory grill from the plastic engine shroud. (Heaven forbid a squirrel jumps in there.)
Aim the scoop slightly down toward the road NOT at 90* but more like 120* from 0. The road surface creates a barrier that the air can not push away from.
No worries in the rain either. I have an inner rotor set up, and water does not/can not accumulate due to the velocity in there.
I know... This stuff is soooooo cooool!