there should be 6 drain holes in the floor pan, two in front of the front seats, two behind the front seats and 2 under the back seats.
6 unless you find rust, and then its all cutom from there on.
taking the carpet out was the 1st thing i did the second day i got my vit. also, if you plan on hosing the floor out once in a while, maybe hose it out before the rhino liner, and see where the water pools up. if your happy with it, or if you have a water/aqua vac, then its all good. sometimes i have a hard time getting rid of all the water, as the floor does not always run towards the drain holes.
probably the easiest way to hose out the floor, is to have either front wheels on ramps, or the rear wheels on ramps. this way, you will have ALL the water at the front or at the back of the floor. aqua vac saves a lot of stuffing around.