It's kind of looking like flour on the leaves but it goes up some stems. Also a leaf pattern like it's coming from the plant, following the veins.

I'm thinking about having a massive trimming tonight when they wake up.

Or would it be better to spread it out of 2 or 3 days?

You follow a stem back to the main stalk and cut it on a diagonal as close as you can to the stalk?

Thanks