I think your friend was just a little confused, i have done a lot of research on pruning since i use cfls and do not get as good penetration as you do with that nice little hps you got there. From what i have read you shouldn't trim any fan leaves. Now what you can do is trim the bottom few flowering shoots. Why would you want to do this? Well those bud sites at the very bottom are going to be using your plants energy to produce bud which usually only end up as little popcorn buds and eventually after harvest just shake, kind of a waste if you ask me i like my nugs dense you know. When you cut a few of these off all the energy that it would have used producing those little buds will go to the main cola or other bud sites closer to the light giving you much thicker buds at the top. So just leave those fan leaves from now on man, if they don't get enough light then they will just use up all there foods and stored light and probably fall off themselves when they are ready. No sense in wasting all that. Oh and when you cut off those bottom shoots just get some rooting gel, dip them in and stick them in soil, perlite, or a little bubbler (easily done just use some kind of gallon jug or something and throw an air stone in there root them and you have some clones for your next grow.
