Tapered roller bearings require preload when initially set up. They don't need any "play". I've never torqued one in my life, but if I had to guess, I probably go 10-12 LB FT. If the cotter pin hole doesn't line up where I feel good tightening it, I tighten to the next hole and put the pin in. Never back it off to line the cotter pin up.
I wouldn't say "never". If I was using a torque wrench at 12 LB FT and I was in between slots on the nut I would back up. Individual preference I guess. Now on a tapered fitting, like a tie rod end, well that's a different story.
