I think having the pierce effect move along the direction of the beam shot is not quite how it should be done...
If you observe the FS2 intro, for example, it's really more as though there were a single burst of material emitted as the beam first exited on the far side... however achieving such an effect might be kind of difficult. As for the slash effect, it seems like it was yellow in the cutscenes.
Another example is the GTC Vigilant ambush cb anim... it's a yellow trail flush with the model (sort of like decals, but unfortunately that code is somewhat DEAD)... but there's also some particle spew, it seems.