When I cut, I normally rehydrate something like this (and it's what I'll be doinhg next week!):
-Slowly sip 2L of water with 2 sachets of diarolyte/pedialyte. Break a couple of bananas into chunks and eat in bits.
-Have a protein and carb/MRP shake ready, with creatine and get that down.
-Have another 2L bottle of the above ready to go and keep drinking it, but now start with some small portions of wholemeal pasta/rice cakes/brown rice with a bit of veg and a protein source.
-With this done and small meals at about 30min intervals, and a few hours after hitting the scales, then you can begin to eat bigger portions of regular food and good carbs.
-Pig out, but make sure you're getting plenty of fluids in until your urine is clear...and then some.
This is with a water and carb depletion cut day before weigh-in, not a same day weigh-in.