I have a 1 hp, 5000 rpm motor and it works real well for most things with
speeds in 3 pulley settings approximately the same as yours. This is
obtained with a jackshaft. I have turned up to 18 inch bowls and you can
turn it down slow enough to be very comfortable. My top speed in top pulley
setting is 2000 rpm and the top speed at lowest pulley setting is between
400 and 500 rpm, so just about the same. My motor and controller cost me
$50 or so from Vega when they bought a whole bunch of surplus. I can
actually turn it down to something ridiculous like 1-10 rpm or less in the
lowest pulley setting.

I have a reversing switch and a potentiometer mounted in a white painted box
from a home store. I bought a blank faceplate for the box and drill holes
for these in the face. The wires are in a split, corrugated flexible tube
like used in some autos. I epoxied magnets on the back of the box and can
move it to different positions on the lathe.

I turn only bowls and sometimes I wish my speeds were a little lower so I
could be at the full 1 hp more of the time. Pens and tiny objects might
want over 2000 rpm. The larger the motor you get, the less optimized your
pulley ranges need to be.

Derek