I myself, tighten them from hand tight...then between 1 1/2 turn to 2 turns. I've been adjusting them this way since the mid 80's, and have never had a wheel come apart or any other issues, besides regular maintenance of checking them periodically for any that may have loosened up, and just simply re-tightening.
Now that being said...I do not know what I'm actually torqueing them too. They're not extremely tight(which you do not want them to be too tight), and loose enough so they have some "give" when you squeeze them with your fingers.
I was taught doing it this way back in the 80's from one of the mechanics of a local expert rider here in southeast Massachusetts. I'm not saying it's the correct way, but I've never had a problem.