That excessive backlash comes from wear on the gear teeth. That's why I said you're not very likely to get good results trying to set things up to factory-original specifications. The most obvious indicator of excessive backlash is a considerable amount of free play when turning the pinion yoke. If you're considering buying a complete unit and the owner doesn't want to open it up for an inspection, the free movement of the yoke is a good bargaining point on price. Don't assume excessive slack can be adjusted out!
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!