I don't know anything about that one, but there should be a button or dial to adjust output.
If all else fails, get a Tekonsha Prodigy.
This on both counts. If you have a time based controller they tend to lock the brakes when you drag the pedal while slowly slowing down. You can turn the gain down, which slows the initial aggressiveness of the brakes, but they still ramp up over time. The Prodigy is inertia based. It has a small accelerometer/pendulum that controls the brakes. The harder you brake, the harder the trailer brakes. If you lightly drag the brakes of the truck, the trailer does the same without lock-in up. I have had both and prefer the prodigy.
