Re: is it ok to cut off shade leaves during flower ???
I would just leave (no pun) them alone. It was explained to me that they are like the plants power station where the energy and factories are stored. As your plant approaches the end of flowering these leaves will gradually go yellow as the plant uses up its stored resources.
When I was a boy i removed all of these leaves and it stopped dead in its tracks. Might still be flowering today.
I only remove fan leaves if there is a problem with them eg badly damaged.
Might as well enjoy yourself as you are a long time dead