I've run speedy sleeves for thousands of miles without a problem, and since they're stainless, they're far harder and more durable than the original balancer hub. If you use some sort of V block or a piece of angle iron to spin the hub on and a MIG, you might get by with welding the groove. That would only be my choice of repair if a sleeve was not available.
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!