Thanks Brian. I carefully measured to ensure that I minimzed the open space in the cases to maintain maximum transfer velocity. The reeds sit about 3/8" off the crankshaft. The plate blocks the gapping std hole and I positioned the reed all of the way to the back side of the engine. The pic doesn't show it, but I also made a filler block to close up the front half of the case hole. All of which is effectively like stuffing the crank.
If you've seen my YT videos on Carb Options & Reed Valves, you'll also see where I had the benefit of blank cases to work with, and that my first 4-petal Yamaha reed setup wasn't ideal with a lot of extra open space.
These Dio blocks have a lot of capacity and so I wanted to minimize the space to maintain a strong carb velocity. That's why I made the stuffer; to cut down on turbulance and provide some fill so the transition from the carb to the block issn't too great.