Thanks again for the replies.

In respect to the setup:
Are there any pitfalls to setting layer height somewhere around the capability of the machine? I'm assuming that this will create a smoother part.
Next, is this calculation for the capability of the machine's minimum layer height correct:
M5x1.5 lead screw = 1.5mm for one full revolution.
1.8 degree steps = 200 steps per revolution
1.5mm / 200 = 7.5 micron z axis resolution ???

Even giving it room for slop, the .1 mm or 100 micro layer thickness I've seen recommended for higher quality prints seems too large. Is it within the realm of possibility to print at say 40 or 50 micron layers?

The extruder I bought came with a .4 mm nozzle. I also bought a .2mm and .3mm nozzle. I'll probably start with the .4mm and work my way down as I learn. What problems might I experience?