I always thought that spring inside the handle was for the button at the end of the handle, just to put tension on the ratcheting handle teeth.
You can adjust it under the center console (Where the rear ashtray is). It's been a while but there should be two lock nuts on the threaded rod coming from the rear.
I used to rent a house with a steep driveway and always put the e-brake on and left it in 1st gear. One cold morning I wanted to warm the car up before i left and took it out of gear. I went into the house for a couple minutes and just as I was coming out it started to roll down the driveway! There was nothing I could do. I tried to run after it but there was no way to catch it. It brushed a tree at the end of my yard, went across the street and something turned the wheels right before it was about to hit my neighbor's Explorer. Instead it bumped the tree in his yard. Broke the mirror off and puckered the rear bumper cover. Could have been worse, but there's nothing worse than feeling so helpless as your pride and joy rolls away out of control!
From then on I parked face downhiill because the e-brake seems to grab way better forward.
I hope you're able to adjust yours and I'll look into the adjustments more but I think that was how I did mine.