I just use the default settings Dave but when it comes to the guiding settings I use RA/DEC not RA+DEC. My mount doesn't like it when it gets directions to move in both RA and Dec at the same time.
My scenario would be slightly different to yours. I'm guiding through my handpaddle port rather than through the Star-Mate. I haven't quite got that worked out yet.
According to Martin I may have a couple of wires around the wrong way in the serial plug.
How are you setting yours up as far as connections are concerned?