Spoilers spoil lift. They can be put from 30% to 75% chord. On landing and tasks like that they are good to control the flight path of the airplane. They are used with flaps on landing to control the flight path of the airplane. Flaps go out at big deflections to get a lot of drag and some lift. Then you set the elevator deflection to control the airplane attitude, etc. The spoilers then can adjust the vertical position on the flight path without affecting much else. When you touch down all the spoilers come out and keep you there.

When you use ailerons on the trailing edge of the wing on your model and deflect them up you get a nose up airplane pitching moment. Remember that they are located a significant distance from the airplane CG and that is what the moment is about.

They might be spoiling lift but also create the moment. To get rid of lift without the pitching moment you need to move them to 30% to 40% of the wing chord.