concur, Edson speed knobs are adjustable to most. i had to trim the set screw on mine to get it tight but Edson is the way to go if adding a speed knob as there are no protruding sharp stuff after install to catch clothing or scratch people.
i'll eventually sell mine since it sits in storage after i replaced the whole wheel with different one which had an integrated knob.
Current wheel has the knob on the main rim of the steering wheel but i think i prefer the know to be set in on a spoke as it has a habit of ending up in a "dangerous spot" that can cause the driver to hit a high "B flat" if not careful, if you know what i mean :doh