First I made a cardboard template of the approxiamate shape that I wanted and marked it out on masking tape applied to the area to cut. Next I cut the three "corners" with a step drill bit to get a nice radius. Then I went to work with my trusty Dremel tool and cutting disc. I painted inside the cut edges with some red touch up paint for a finished look. Lastly, I cut up some of the grill material I had from an old wastebasket (I've used this stuff for other vent grilles), hit it with some flat black spray paint and secured it using 3M adhesive tape.
I think it looks great because the black screen ties in with the black Dzus fasteners, etc. I report how well it works after my next day.
I also found a used Euro Racing quick turn throttle on one of the forums and installed that. Had to get into the airbox to install the cables: Hence, the diassembly! This throttle housing includes three different sized cams that give different degrees of total throttle twist. I have the largest (quickest) cam installed and it's about 1/4 turn now. I report back on the results here also....