I've had a pretty fair success rate balancing a driveshaft by clamping a 1/2 oz. wheel weight to the shaft at one end or the other with a big hose clamp, and test driving the vehicle. The floorboard and seat makes a pretty good monitor of vibration. Move the weight around the shaft in 1-inch increments until the sweet spot is found, then tack weld a steel washer or two in that position for a permanent fix.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!