Its nothing fancy but I blocked my grill and made a partial belly pan today. I will slowly add more to the pan as I find time. I have no scientific data but on a long hill that I regularly EOC on, my speed was 10kph (90kph) faster then I have ever coasted down the hill. I even had to hit the breaks coming into the 50km zone which I have never had to do before. I was also able to P&G over a hill that I have never made it over before
The grill block is 1/4 plywood painted black. In the summer I may try to make some shutters that I can open as close but for now this will work.