Plenty has been posted here, there are tech articles elsewhere and Lokar has their own instructions.
The ratio has to match 1:1
What I did when I ran two of them:
Measure: Carb throttle shaft centerline to the kickdown ball pivot (as mounted in the correct throttle lever hole) centerline.
Duplicate that measurement on the lever and drill the hole. Centerline to centerline exactly. Make sure your drill bits are sharp, good quality.
Then hold the throttle wide open, pull the cable all the way forward until the kickdown lever stops, tighten the cable set screw.
You want the kickdown lever to be all the way back when you hit WOT.