To go by Manufacturers spec would probably the wisest thing to do but when I am at it I dont want to dig out specification nor my regular Torque wrench I have in the Shop. Most Guys with mechanical experience since Childhood know what feels right and what not. Generally speaking Screws/Bolts on Bikes are not really high quality meaning they strip the Threads quite easily and/or the Bolthole they are suposed to fit into. Just tighten within reason but try not to overdo it. Good practice is to check all fasteners and retighten if needet at least twice a year. All I have to do now is heed my own advice - Cheers.