5-6 pounds is really not that big of a deal. And the weight class is actually 220.5, that extra half pound helps sometimes.
for a 24 hour weigh in, I usually drink a shit ton of the week before and cut off water at around 6pm for a 9am weigh in. I'd be worried about decreasing your food intake that much. I think you'd be fine eating normally wednesday and thursday( avoid carbs and salt if you are that worried) and then try and get to small meals in friday morning.
To put things into perspective. you could easily take a two pound shit, and 4 pounds of water is about a half gallon. Not a huge amount to piss/sweat/spit out.