How to get the ghosties to appear on cue?
Volume Volume volume.
You have 37 spirits available etherally stringed to that buiding and also be near a cemetery and rely on the show times to coincide with the wobble of the earth's magnetic grid, so twice a day there is a wave of activity. At Jims latitude the grid sweeps about 43 miles back and forth and he is in a dead zone for other interference like cell phone and radio signals.
Oh, yes and Jim is actually dead too. And he passes a lots of gas that things can be projected onto.
All true Gregg and psuedo-scientifically correct. (It's my best psuet!)
Even a deadman has to run out of passable gas eventually. Come visit the Ravens Grin and watch Jim to see if you might be the extremely lucky one to be here when that happens!