Keith, I approach this slightly differently by the looks of things.
I would only maintain 1 publisher set for all the master drawings.
The subfolders can output PDFs to separate files containing all the relevant pages e.g. all the A1 pages would be in one file, A2 pages in another file etc. You can then simply open the relevant PDF and send it to the relevant printer.
I'm still coming to terms with the new change manager but I think you should be able to do something similar so you are only publishing altered drawings to the PDF files as well.
Publisher is quite versatile once you get to know it but I have nearly always used it for PDF output and then sent those files to the printer rather than printing direct from publisher. It also means you can check your output before wasting ink
If by the sounds of it you have two printers set up correctly then life could be as simple as dragging the PDF file to the relevant printer icon / print que. and letting it do the rest but you need to have the defaults for the printers set up correctly!
Apple iMac Intel i9 / macOS Sonoma / AC27UKI (most recent builds.. if they work)