Modified kraken home made 3d printer

im designing a 3d printer on solidworks my goal is 800 mm in X 400 mm in Y and 500 mm in Z

im open to suggestions.

my design is based on the ultimaker 2 for x and y motion.

z motion is up for opinions.

im guessing im going to need a board that is compatible with master and slave for marlin.

gear box steppers yeah or neah, and what sizes.

the linear rods are going to be M12 with LM12LUU bearings and some type of radial bearings for end support.

motion for x and y is belt dri