OK, sorry to but in here but just want to help, the weaon_equip.ini references everything, just read the names of the FX_Type = FxBasicAppearance and FX_Type = FxRectAppearance in the anl. Some effects also use a FX_Type = FLBeamAppearance. They will have _flash, _proj, _impact and other extras attached to the names. These are pretty simple to figure what part of the weapons effects they are used for and these are all used by the weapon in the ini.
As FF said, node_color under Node_Name = ku_capgun_01_proj.app (_proj for projectile ;)) is what you want to change.
The appearence sections are what you want to change for things like opacity (or varying levels thereof), color (once again varying levels if you want) and size. (also if you want to be flashy and create animated textures you would specify how the animation plays under the appearence section but leave that for now).
So if you want it to be say green then you would change it to this:
SubEntry = 0.0000000000000000, 0.0000000000000000, 1.0000000000000000, 0.0000000000000000
SubEntry = 1.0000000000000000, 0.0000000000000000, 1.0000000000000000, 0.0000000000000000
So now it will be green from start to finish, but you could have a rainbow effect too:
SubEntry = 0.0000000000000000, 0.0000000000000000, 1.0000000000000000, 0.0000000000000000
SubEntry = 0.2000000000000000, 1.0000000000000000, 0.0000000000000000, 0.0000000000000000
SubEntry = 0.4000000000000000, 1.0000000000000000, 1.0000000000000000, 0.0000000000000000
SubEntry = 0.6000000000000000, 0.0000000000000000, 1.0000000000000000, 1.0000000000000000
SubEntry = 0.8000000000000000, 1.0000000000000000, 0.0000000000000000, 1.0000000000000000
SubEntry = 1.0000000000000000, 0.0000000000000000, 0.0000000000000000, 1.0000000000000000
Just my 5cents, hope it helps a bit more.