When it gets hot outside in the afternoons plants naturally stop or slow their transpiration, thus they wilt. Wilting in the heat of the day is normal, especially on plants that are overwatered. You should water in the morning hours ONLY when the plants show a need for water. They show a need by wilting but only in the mornings before it gets hot. I doubt if it is root rot although it is possible from the over watering, but, if it is there is nothing you can do about it now. Just stop watering until the plants are showing a slight wilt in the AM and when you water COMPLETELY SATURATE the plants soil. Water slowly until water stands on the soil surface, probably about 20 minutes with a slow trickle from a hose. You will water about every 7-10 days. Watering by sprinkler IS NOT A GOOD THING. You get the entire plant wet. When this happens you are inviting fungal problems i.e. early blight plus other fungi that are just as bad or worse. You do not want to have the foliage wet especially at night. It isn't so bad during the dayight hours because the sun will dry the leaves. Most fungi is transmitted to the plant by water splashing up onto the leaves and the fungal spores are in the soil so try to avoid this. There is no such thing as watering too much at one time but you can and will kill a plant by watering too often.
BTW we are neighbors, about 75 miles apart.