Charles- I did notice what you are talking about and made mine with a bit more radius, for a bit more meat at the unsupported edge. This left me with an area of metal at what will be my welded edge that could probably be trimmed a bit for weight savings, but I think I will leave it on. I feel it will support the engine vibration evenly in both horizontal and vertical, station one tubes. That is the way the plans show the welds done. So much for "feels good engineering".
Attached is a photo of one gusset just taped in place. The white dot represents where the hole will be and the distance to the unsupported edge is about 3/4 ". Rich.