Looks like time for a little creative metalworking. You could notch, trim, cut as you need to make clearance. Curious though, have you tried giving it a run without it on there? Every prop seems to have a different feel, and it becomes largely a trial and error process. As for your vent plugs, again this is somewhat a trail and error process also. Some are designed to be either in or out, but many other systems have varying size holes to customize to your application. Designed to allow the prop to slip during the hole shot to bring the engine RPM's up, the holes are no longer in play at speed as the exhaust simply flows to the path of least resistance out the center.
Speaking about ventilation holes in props, David, I'm curious to know how your performance is with no exhaust through the prop. Might be for a new thread, but I also run a small hub Trophy on my CVZ, but its converted to thru hull, so no exhaust anyway.