I have the same problem. I did the throttle hang fix, and went with the larger diameter hole in the center and it seemed to drop off way too quickly. You had to almost sorta double clutch it to keep the rpm's up inbetween shifts, even with the fastest shifts from the shortthrow it still dropped off for a rough reingagement. So I took it out for now.
Should I try a even bigger center whole, or whats the idea?