i had to tune my 18rg carbies on the w/end, i've now got them tuned just as well as the pros (did get my old solexs tuned at 3 different tuning places before they realised i had the wrong jets- just goes to show the pros aren't always the best).
I screwed them all the way in, then unscrewed them ALL exactly 1 and 1/2 turns out, then slowly screwed all of them out one after the other just a bit (like no more than 1/16th a turn), the idle should pickup, then repeat this until the idle starts to drop.