The one way clutch helps,but it isn't neccesary.If the balancer\pulley is wobbling,then something is wrong.Is the crank gear on tight and flush ? Maybe the crank was maching incorrectly,or the snout is bent.It could also be the balancer.I'd pull the balancer off,and check the runout on the crank gear.You can use a dial indicator.If it's OK,then it's gotta be the balancer.If not,then it's a problem with the crank,or the gear.
The one way clutch on the alternator pulley will stop the serpentine belt tensioner from "dancing" at idle, but it won't straighten a wobbling pulley. Be careful not to confuse engine vibration with pulley wobble, use the engine as a reference to determine if the pulley is wobbling, not the car body. Very often the older style harmonic balancer is not properly pressed together and will wobble, sometimes takes a few tries to get a good one. The very newest style harmonic balancer has the pulley machined onto the portion that is bolted onto the crank pulley and the weight ring is on the inside. If you have one of these and it still wobbles then something is amiss.
I believe Altrom carries the pulley,but it isn't cheap.It think it's $115.00 or so.I'd try some local scrap yards,as a lot of cars out there have the updated pulley.You could also try a local alternator rebuilder.Was nice to meet you,glad you could drop by.If anyone else in the GTA needs something looked at,feel free to drop by.