Short story trying to get an old Seiko Smart Label Printer (which only comes with a serial port connection) working with PCLOS 2009.2

Have also been playing with an SLP100 a friend has loaned me, which has both a USB and a serial. Basically cannot get serial printing working fully.

The SLP100 works fine via USB off CUPS using the PPD provided from seiko website. CUPS prints a nice test label print.
Seiko make a nice simple win app to print the labels, but no Linux equivalent that I can see. Can print from Open Office etc, but setting margins is a bit of a pain.

I then tried to change to serial connection off /dev/ttyS0
I had to change permission on the cups serial backend.
Trying to do a test print never works from CUPS. depending on what permutation of SetSerial attributes I have tried, CUPS either says the print job completed ok (but nother ever appears) or just sits there waiting (saying processing since...)

I did try loading various versions of the Seiko software under Wine (1.1.26), most installs failed though one seemed to nearly complete and left in a seemingly usable state.
It attempts to auto detect the printer.
This never detects via USB
But it does detect on correct port when connected via Serial

If I try to print a std address label with not much text, it works.
If I print a label with reasonable amount of address it works nearly!
Again depending on setserial settings,
It either prints most of the label but not all and does not advance label to next, and the green light is on the SLP.
If I request same label again it prints from where the other has stopped and prints the same amount again, still green light.

But other times it will print much less of the label and the status light on the SLP will flash amber/orange, and no more labels can be printed.

I installed SLAP from the repositary and it works (as well as it does) fine. prints the label and advances label ready for next, which tends to suggest that the serial connection is fine, it't just CUPS/Wine have issues with settings or maybe a buffer ?

While the SLAP works it is very slow and tedious when doing a new or adhoc label. Something the Seiko app is brilliant about shrinking the font so your content fits.

Any suggestions on what sort of settings I should have for CUPS serial ?
Or why Wine may seem to have serial port buffer limitation ?