And you base this info on what? You obviously know nothing about timing for a show. Hope this helps.
I know i have competed numerous time too.
1st For fullfilling your muscle,you need carb and WATER
to make water retention IN your muscle.
2nd To get rid of water,you dont have to drink water.(Maybe you use some kind of supplement like potassium,but those get rid of water of muscle too.)
And dont forget,diuretics are banned in ifbb pro contest.
This is the reason why you cant do it same time.You have to begin to eat before you start to restrict your water supply.
And most of pros dont do such a high risk way like you think. Its only amateur like you do.