You have to have enough pressure to activate the fill valve to fill the tank. Water pressure only affects how long it takes the tank to fill, not the flushing. We would recommend at least 20psi in order for the fill valve to operate correctly.
No - it is only 17" from floor
This bowl can be used with the 10 or 12" rough in. It is the tank that determines which rough in you use.
This model has a 2" gravity fed flush valve. This model requires a 12" rough in but you may dry rough it in to see if you will have enough clearance between the tank and the wall.
The rough in is measured from the finished wall to the center of the floor flange.
Please contact our customer care line at 800-442-1902 for assistance. We will need to know the color of the flapper.
I am sorry but we do not have anything with those measurements.
The 4392 does not require a special seat. You can purchase any elongated seat you would like.
You can adjust the water level in the tank by adjusting the fill valve. This will stem to the bowl then.
You will need to adjust your fill valve. There will either be a screw on the top of it or a clip on the side that you will adjust.