Thumb Choke

I'm in need of a thumb choke. Darrell Taylor is out of them at the moment.
I understand people have made them with a BSA thumb choke, but my fabrication skills are useless.
Could someone explain how they would fabricate these to fit the two bolt holes on the light switch and what cable to use?
I understand people have made them with a BSA thumb choke, but my fabrication skills are useless.
Could someone explain how they would fabricate these to fit the two bolt holes on the light switch and what cable to use?