Personally, I like to replace the bearings on the carrier and pinion. After the depth is set, I usually check the book for the back lash as long as the pattern is good.
You can get a tube of "Persian Blue" ink at the AutoParts shop for checking gear patterns. Use it with one of those acid brushes to paint the gears and check the contact pattern.
As a rule, center ovals are good.
Hope this helps.
