query - 2HP PM DC motor controller - pointers please

I recently purchased a 2HP PM DC motor, hoping to build/buy a
controller so that I could use this on a small lathe. For those
interested, it's a Leeson motor, designated 120v 14A, 4800 RPM.
Model C42D340T7A. I plan to reduce the maximum speed then feed it
into my existing lathe drive system.

Several questions:
0) the motor doesn't have any designations about reversability. I
know electrically it works, but I'm not sure if the brushes are
rated for reverse motion. As I manually rotate the shaft, the
brushes sound smooth in one direction and click lightly in the
other. Should I assume that the motor is designed for one direction
rotation only?

1) I've seen a lot of postings discussing 90v DC from 110v AC and
180v DC from 220v AC, but little to nothing on driving a motor rated
for 120v. I'd get plenty of power out if I ran it at 90v, so I'm ok
with a controller that does the basic 110AC -> 90DC conversion. Any
reason why this wouldn't be suggested?

2) If I do run it at 90VDC, that's 3/4 of 120VDC, so would I simply
then treat the controller needs as 1.5HP / 90 VDC and 10.5Amps?

3) I've no problem making a tach circuit to provide closed loop
speed feedback, and from what I can tell, a PWM circuit will provide
the best performance. I've made my own PWM DC servo motors before on
a small scale using encoders and DC gear motors. Is controlling a
large, PM, brushed motor of this sort simply a matter of scaling up?

4) not having experience in higher voltage/power design, I'd
appreciate a pointer to a web site with some designs. I'm not
looking for someone to give me a tutorial on this forum, and I've
done a lot of web searches but they've turned up fairly cold when it
comes down to real designs for these types of controllers.

Thanks for your help.
-Ted