Well now you know that you definitely underfed the last ones but I am not sure that you are still going to be giving them enough this time around.
You should be putting the food out early in the morning and leaving enough for them to last all day.
If you don't want to feed them around the clock you can just pull the feeders out at night but I wouldn't be letting them run out of food.
Did you have any losses? I would thin that not having enough food would cause them stress and usually that brings on other issues.
I know when hens are not fed enough they will go into a moult from the stress, same with lack of waterjust wondering about the meatbirds.
I personally would not be worrying about measuring cups per bird, if you want big, fat birds you need to let them eat all day.
You asked about water, rather than worrying about being home to refill the waterer or having them run out I would use a larger size or buy more so they have two in each pen.
I use a 5 gallon waterer for my birds and I have between 50-100 in each batch, it works fine.
I add a couple of tablespoons of apple cider vinegar to keep it from getting slimy in between cleanings, just don't use it with metal waterers.