I had to redo my plunger and thought I'd share it. I use a gamepad directly attached to the plunger. My last gamepad lasted a couple years, and I had to replace it. I use a deadzone of 0% on this. The old plunger was a bit more sensitive than this one, but it works just fine. It's a nice alternative to expensive kits. Feel free to share this pic on other forums if you think it might help someone.
As you can see I'm using a hoseclamp with a drywall screw through it. The clamp is between the 2 washers so if the plunger is rotated it won't break. The hoseclamp will just spin. The gamepad is just held in place so it can't move, but it's not taking any more abuse than if you moved the stick with your finger. If you have the travel adjusted right, it won't take any abuse.
So in short:
1. Get a gamepad and setup the correct axis before you mount it.
2. Mount it securely and make a linkage (allow for travel).
3. Profit.