"Lightning" effect on stage - any tips for equipment?

Is your lightning on stage or off stage as the set design influences the lightning effect. If it is offstage then the lightning may only be seen through a window, or perhaps lighting a staircase that leads off stage. The strobe is the most effective lightning effect due to its high brightness, but needs to be slowed down for one or two flash durations. I have a manual strobe I have modified for this purpose. A dmx controlled stage can be set for a very slow flash duration and can be controlled as a cue or using a flash button. As most people know, light travels at approximately 186000 miles per second and sound travels at approximately 1100 feet per second so the light and sound will not be in sync. Some astute members of the audience may even time the difference to see how far away the lightning is to see if it fits in with the script. The lighting operator will cue the sound operator for this effect. You also have the choice of using a lightning gobo projected onto a surface but would normally only be used for pantomine type shows. This is one of those occassions where a special is used for a very short duration but helps to set the mood and atmosphere of a production.