Somewhere in the forums Nebula points out that plants may need extra water in hot/dry/sunny conditions, but they still need only the 'normal' total nutrients. Using full-strength nutrient solutions when all the plant wants is water may overdose it on nitrogen. Probably doesn't matter whether they are 'slightly wilted'. Try to determine what is appropriate to your local climate (mine is hot and dry, so this is an issue for me). Watch for signs of fertilizer burn and adjust your fertilizer concentrations on a long-term basis rather than trying to guess what the plant needs on a specific day. Nothing wrong with giving them extra water with zero added nutrients on extra hot days.