How to create an adjustable spoiler

How would one create an adjustable spoiler so that you can adjust how much downforce(dragCoef) your spoiler creates? I have the Variables thing configured, but I don't know which "unit" and "catagory" I should use to make it work.

Thank you!

 

I've tried to get it to work with this syntax


"variables": [
["name", "type", "unit", "category", "default", "min", "max", "title", "description"],
["$dragCoef", "range", "dragCoef", "Drag", 200, 0, 1000, "Downforce", "Adjusts Wing Downforce"{"stepDis":0.5}],
],

Then where it starts the Triangles I put

{"dragCoef":"$dragCoef"},

What am I doing wrong?