Jhn, please don't go cutting off any leaves to help with light penetration. The less leaves, the less growth. Simple. It's better to tuck the leaves out of the way to let more light in. Just be gentle and, you know, use one finger, push that leaf down and a little to the right..., up under there...., good. See. Leaf is fine, light's getting to that bud site better now. When I get some leaf that's yellowed and not coming back, I take it off. Some people will leave them on till they drop. Just personal preference.
You asked why some people will "cut their leaves in half". One example would be where my Afghan stuck her leaf up(over) into the light. Half of one of the blades got burned and was crispy and brown. So you just cut that part off. The rest of the leaf is still fine and dandy. Down on the lower leaves, I accidentally squished a few leaves between the two pots in my cramped space. They turned yellow and then brownish on some parts. So the bad shit got cut away and the healthy stuff stays.
As far as Worm Castings in combination with other nutes: Don't make it too complicated. I'd advise you to just stick to the nutes you're giving them now, if it's working for you. You know the saying, "If it's not broke, don't fix it.". That said, I can't really see the harm in using WC in combination with other nutes. Make sure you know your product. Does it have a lot of Mg, for example? Then watch out when using in combination your other nutes so that you don't cause toxicity from suddenly having too much Mg.
Just feeding worm tea by itself is safe as can be. It's a very mellow, all round nutrient source. You can use it often and liberally. There're lots and lots of goodies in there- lots of calcium, magnesium, zink, iron, and all the micro nutrients and things that your soil wants. It can be brewed and used as a foliar too. You can use it as a top dressing on your soil and then feed
through that.
21 days is quite normal for them to flower.
I don't know how often you're rotating your pots. Sounded like you were doing it very often. What I do is rotate them every twelve hrs, 180°. This way they can really work with the light. If you turn them at say, 12:00, and that one flower is basking in the light and getting her sexy going, then two hrs later you come and turn her away again, she's like, "Hey F*er! Where's the light?!". That's just my 2 cents though. I don't know what's best there. That seems to be what's best for me.
Edit: Forgot to mention that I do the pot rotating like I do with my lights on 24/0. I forget what your light schedule is. If you were on say, 18/6, then I would guess that if you turned them once a day, or every 18 hrs, you'd be good. No experience there. Just a guess.