We've always shimmed with a scrap of the dust shield (you can see it in the pic). Never any end play, no obvious drag due to preload. Obviously without it there's way too much preload and the bearing doesn't spin at all.
Interesting. I leave out the dust shield and have no issues, and very minimal (if any) end-play. Usually I end up with zero preload and about 12-ish in/lbs of bearing drag when measured with my calibrated hand/wrist. It feels like a well setup pinion bearing.
can you expand? We did wheel bearings last week, didn't shim anything..
Early Dana diffs used shims under the retaining plate to set axle end-play. You could do the same with a shim under the bearing race/cup. Reduces pad knock-back and improves bearing life unless it's set too tight.