when to cut

The tips always look like this for me when the harvest is approaching. The problem with the lower buds can be solved with additional side lighting and/or by removing the large leaves so that more light gets down.

I don't think those are burnt very much at all! They look okay to me, but if they are large fan leaves covering budding sites they can be removed but I wouldn't remove the last 3-4 sets from the top until flushing begins. I've learned to leaf "tuck" and expose the budding sites without removing the leaves. Hope this helps!