Beginning to build my Z-axis.

[zonk2]

I am about to assemble the Z axis on my homemade CNC router and I would like some advice before I start. My table is 4 by 8 feet and the gantry is just over 4.5 feet wide. The height from the bottom of the Y axis (gantry) to the top of my table is appr. 10 inches. The Z axis will move back and forth on linear rails.
I have a Freud variable speed (10,000 to 22,500 rpm) router, 3 1/4 hp, 15 amps that I am thinking of using for my spindle. I am using 3/4 inch aluminum for the the 2 pieces of metal that will make up the Z axis, which will be separated by a linear rail for the up and down motion, and moved by a ball screw.
Will the Freud router be a suitable choice for the spindle, even though it will take a bit of work to mount it securely on the plate of aluminum.
Would it be of any advantage to be able to manually adjust the router so that it could be rotated to being parallel to the work table or perhaps 30 and 45 degrees from normal as well to drill/mill in different positions if needed (something like a manual rotary table).
What would be the best height above the work table for the bottom of the Z axis in its lowest and highest position and how much travel to have in the up and down motion.
Since the piece of aluminum that will hold the router will be 8 inches wide and fairly long, and in a "L" shape, what can I do to reinforce the Z axis to make it more sturdy so there is no movement when the spindle is all the way down towards the work table.
Lastly, to decrease the 8" width of the aluminum piece that holds the router, should I mount the router sideways, since the router is wide from side to side but not front to back.