rack and pinion advice

I am designing a 4'x8'gantry router with rack and pinion on the x
and y. Does anyone have any advice on wether I should gear down
nema 34 stepper motors with timing belts and pullys?

I am thinking without gearing down I would get the fastest rapids
and at cutting speed, and I think I would get the most torque
because the motor wouldn't have to run as fast to move the gantry
(I was under the impression that the faster you ran a stepper motor
the less torque you get.) Am I correct in this thinking or am I
missing something?

I was planning on using pullys and timing belts anyways figuring it
would be easier to upgrade to servos if I wanted to in the future.
I just cannot decide if I need a 1:1 ratio or something else. If I
did need a different ratio does anyone have advice on what that
should be? I was figuring on using the smallest spur gear I could
get, or do I need something with more teeth engaged.


Another question: I was planning on using 14deg 20pitch gears and
rack because that seems to be the cheapest route at Mcmaster, and it
seems mcmaster doesn't carry long lenghts of 20deg rack.
Does 20deg make much of a difference on smoothness and is it worth
the extra expense? (and does someone have a better source for 20deg
rack?) How about gears and rack with helical teeth, I saw
somewhere on the net but can no longer find the site, is that worth
while?

any other advice you rack and pinioners and give would be greatly
appreciated.

Troy