"there is no way to have the stems worn into the eccentrics"
yes there is, the eccentrics do get worn, I had to replace them on two of my 2002s. Worn eccentrics make valve adjustment very difficult to get right. I had a lot of practice before I rotated the eccentric around to where I could see where it met the valve; then the problem was obvious and I got new eccentrics. Not all were replaced; I had a look at all and chose to replace the ones that visually showed wear.
I also don't believe there has to be some "tick", but one person's ears are different than another's. The clearance is very small, there's oil there, and because of rounded surfaces the cam/rocker/valve contact speed is not as great as one might think.
