I have a projector behind the stand on the map (has four cylinders poking out from it) which I cannot get to work properly because I cannot find the entity I am looking for to do what I want or I don't know how to use the entities I could use for the effect I want. I want the projector to project four circular beams of light (all different colours) in a sequence that can be fully customised. The reason why I want it fully customised is because I want to experiment.
As for fully customisable beams, I don't think that's really possible with brush-based entities. You may want to use an env_beam that uses a func_train as ending point, wich can move around, so that would allow much more customizable patterns. A beam can also be set to fade at one end wich would look better here.
Good luck!