I purchased on of the Ali gear knobs unfortunately my T9 lever is 1/2" and the thread on the knob is ?? much smaller. I tapped the knob out to 1/2" and about 3/4" deep but it still sits too high on the lever and the tap will not go further I do not want to force it and snap the tap, my only option is to shorten the gear lever and re thread it. But I am not sure how far to cut the lever down, do I go really short (hopefully improving shift speed) or just enough so my knuckles don't hit the dash. Thanks