Denny, the KDX250 from 91-94 use a 70w stator. That is a pretty good one from the factory there.
Personally I have the UFO twins light, same thing as the Acerbis DHH unit. The ones with the dual round bulbs in them. Those are the best low wattage bulbs out there that you can use. Those lights just use rubber straps around the forks, pretty universal there.
To wire them in, take the lead from one light, wire it to the lead of the other so that they are in series (I think I got that term correct). Then you will connect the yellow and back wires to the other 2 leads. Be sure you have the headlight switch there connected, the wires are color coded there.
Then for the rear taillight, if you are using one, go purchase a LED replacement bulb at an autoparts store. That way you are using about zero watts back there and have the most for the front output. With the stock stator, that will give you plenty good light.