OP fire in general?

[Don Fox]

As "The Rattler" stated, it depends upon the situation. IMO, setting OP fire by individual units is a must; to not do so puts you at a disadvantage, since a good opponent will figure out during the course of the scene what your settings are, and react accordingly.

I find that the settings also depend upon the opponents playing style. If they are using half-tracks or other light armored vehicles in an aggressive manner to draw op fire or "bump" target hexes, then my op fire settings will be much different than they would be with an opponent playing a more conservative style.