This dude knows what he is doing, I recommend you watch the video to ease your anxiety about moldy weed, in this case is powdery mildew but you can see how effective it is and how to do it.
And dont worry as long as you keep the humidity at good levels this is not something you will run into often. If you watered the plant close to harvest you definetely wanna get rid of the big leaves and chop the plant in parts, because even if the relative humidity of the tent is fairly decent your plant will have a lot more water inside. Same with big buds, dont let them touch other buds, space is key when dealing with big buds or humid weed. Oh and good ventilation can help a ton too, since I have to use a filter for the smell I put them on the right side, the filter is on the left, that way the air doesnt circulate directly through the plants, you dont want them to dry too soon either.