Map Projection of Valuation Maps ("valmaps") using GIS

Hey folks:

I've got a bunch of TIFF and JPEG image files of scanned val maps, and I'm using GIS software to georeference them on top of basemaps in this mapping software. It's going pretty well, but then I got to thinking I might get better accuracy if I project the basemap into the same projection being used by the val maps, to minimize the amount of rubbersheeting the software needs to do.

Is there some standard map projection that val maps use? Or maybe it varies by railroad or varies by the year, decade, (or century) it was created?

Thanks in advance for any ideas you might have.

Val maps were created right before world war 1. They employ the conventions of land survey maps in my experience.

Going down this road before you was the Vermont Agency of Transportation which made a GIS layer of valuation maps (in ARC GIS). You can see it at https://vtrans.maps.arcgis.com/apps/web ... 064038df3e
The guy who did it has changed positions, so I'm not able to just refer you to him.