Grain mill hopper question

I have a Crankandstein 2A That Im mounting on wood for a base with motor ect, but I cant seem to determine the best shape for the opening of the hopper into the mill. Do I need to build a hopper shaped as to direct the grain in between the rollers from a narrow gap or can I just enclose the hole top of the mill, stick a five gallon jug on top with the bottom cut off and start grinding.
Thanks Brad

as long as the grains cant escape the sides and go pouring down so fast as to miss the actual grinding....... here is a good picture that duplicates the way i have mine setup http://www.aussiehomebrewer.com/forum/uploads/monthly_10_2007/post-2450-1191829798.jpg

I can tell you what I did. My grain falls through a slot that is about 1/2" x 2" so the grain falls in a ribbon in the center of the rollers.

My hopper is a 5 gallon water jug with the bottom cut out. The neck is mounted in a hole drilled in a piece of 2x4. I cut a 3" wide by 6" long piece of plastic out of the wasted bottom of the jug and put the slot in that. This piece of plastic acts as a gate valve for the hopper. I slide it one way to stop the flow, fill the hopper, start the drill, and then move it so the grain can fall through the slot. No binding, no uncrushed grain falls around the sides.