I doubt there's a "proper procedure" considering that it's an "undocumented modification", with neither the spindle nor bearings being intended for it ... otherwise I'd tighten the nut well, spin the wheel, then back off one slot for the pin

as for replacing them repeatedly, keep in mind that you have spindles with 50 years of wear and abuse that you're trying to use bearings on that do not exactly match the original bearing size specs ... "upgrades", sometimes aren't ohwell

example:
outer ball bearing [B01]: bore=19.044mm/ outer dia=52.8447mm
outer roller [MBS 909001R]: bore=19.057mm/outer dia=52.832mm

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics