I just use Turboprint, with all applications (and printer prefs iirc) printing to "PS:" .
Turboprint is set up with (iirc) HPLaserjet3 driver to print to USBparallel.device unit 0, with a kyocera mita FS1010 (mono laser printer) attached to the Deneb.
Works like a charm.
With multiple USB printers connected, I would expect that these would be addressed as USBparallel.device unit 1, 2, etc (which would be listed under Trident) but I've never tried it, I only own one printer. Then, the desired printer would just be selected from Turboprefs before printing from whichever application.
Regards
Rich