I hate pointing people to my own writing, but have you looked at:

http://www.vintagemacworld.com/osxprint.html

The document is somewhat dated, but the techniques are transferrable to newer versions of OS X. Others have worked on getting the StyleWriter 1500 to work with OS X and you should still be prepared for a lot of wrestling. Even if you get it working you will still be dependent on a Mac OS X box providing a print queue for the StyleWriter, so why not reserve one of your vintage Macs for the role using Print66 and a PostScript RIP?