Earlier, Charles Vincent wrote:

Personally, I would cross drill a few additional holes varying the edge
distance slightly...

I think that's what I would do as well. I'd drill two additional hole
sets that vary the edge clearance in .030 (1/32") increments, and use
the ones that match closest.

My own experience is that tapered roller bearings of this type are
very tolerant of endplay. What they don't like is being crowded
axially. But they don't seem to mind the looseness much as long as
it's not huge. And with the loads applied by your little puddle-jumper
and the taxi mileage over which you apply them, I don't see a need for
heroics here.

The Schreder HP-18 sailplane has the same sort of tapered roller
bearings, and each builder adjusts the endplay by hand-fitting a pair
of spacers. So far, bearing wear has been a non-issue.

My bet is that these wheels use a standard Timken set common to a lot
of cars and trailers, and that for the cost of micrometer precision
you could buy enough sets to change them at annual time every year for
ten years whether they need it or not.

If I was making a ton of those parts I think I'd mill a pair of 3/4"
long slots that spiral about 1/8" axially. That way you'd just twist
the retainer until it snugged up against the bearing, and then tighten
the nut and go fly.

Thanks, Bob K.