Watering with lights on or off?

you want to water in the morning, if you can, so it has plenty of moisture and nutes when it is receving light. I water when it needs it... never when lights are out.. stop any behaviour that you think is important enough to go in there during dark periods -- more for bloom than vege, but still no reason to disturb... simply plan ahead better to avoid that sort of thing. i read the most optimal time to water is moments before the plant wilts... that's impossible to do in most contexts, lol. even so, you still want that to occur in morning rather than night, but if it wilts near end of day you certainly aren't going to stick to that suggestion, i hope. So, worry less about this. sounds like you have an excellent method right now.. wait for it to dry a bit and water. Good root growth will be encouraged by this and you avoid lots of microbial/pest issues too.