Don't worry about it.
Have you actually talked to motorcycle mechanics? Where does anyone get the idea that they are smarter than anyone else? If they can do it, you can do it. If you are concerned then just set the valves to the looser end of the tolerance. Just follow the manual instructions exactly. That's what the mechanics do. There's no magic about it. I've done loads of bikes and cars using manuals and never had a problem.
Modern valves seldom go out of whack after you get a few thousand miles on them. I've had bikes go 40K miles without needing an adjustment.
Have you actually talked to motorcycle mechanics? Where does anyone get the idea that they are smarter than anyone else? If they can do it, you can do it. If you are concerned then just set the valves to the looser end of the tolerance. Just follow the manual instructions exactly. That's what the mechanics do. There's no magic about it. I've done loads of bikes and cars using manuals and never had a problem.
Modern valves seldom go out of whack after you get a few thousand miles on them. I've had bikes go 40K miles without needing an adjustment.