Must be pretty disappointing to go thru all that work and have that happen. I attempt to keep my truck as stock appearing as possible. But upgrades that aren't visible, like roller bearings instead of balls just makes sense to me.
I think using the preload method you used you over tightened rather than too loose on the bearings. My method may not be exactly correct either but I have maintained my small personal fleet of cars, trucks, tractors, motorcycles, and trailers for nearly 60 years without a bearing failure. I also tighten the castle nut until the wheel won't turn (I leave the tire on) but then completely loosen it and retighten until the slightest drag is felt. I grab the tire on the outer edges and make sure there is no play when attempting to rock the tire back and forth.
