Hoot,
You posted the pics and info on this funnel last week when I asked users to "Please share funnelling experiences". I went to Home Depot and found aluminum flashing and made a copy of your copper funnel. I tried a dumpy stock 80mm Protechnic case fan and it was crap compared to the Delta, but it only does like 20 cfm if I'm lucky. My temps plateaud about 17F higher than with the Delta. What a testimony for having good airflow! It was more of a proof of concept model than anything, and a good learning experience. I am going to buy an assortment of high quality, hgih volume fans in different sizes for my experiments. Thanks for the recco on the fan in your post above.
Since the MC462 is built to easily mount an 80mm fan on, I figure that funnelling a bigger one onto it could only be better, plus compensate for the dead spot in the center of the fan.