Decent idea to have Garda units, but their engagement was very limited, and, IIRC, the only loses suffered were at the hands of the IRA/INLA. Those losses would have been in the normal line of duty (checkpoints, responding to criminal activity such as robberies, etc). They'd have never been specifically targeted in the way that the RUC or British Army were. Ambushing RUC/BA convoys and responding to their presence would make much more sense in the context of this mod.
The difficulty of employing Loyalist paramilitaries in an historically accurate way is that almost all of of their operations were carried out against civilian targets. It's great that they're in a mod like this, but they're more difficult to use in a traditional engagement.