I've discovered that there is a more-accurate version of the /loc command: /locvec, which gives the X,Y,Z location [vector] to 6 decimal places. I use it for camera placement for screenshots and /demorecords, but it is probably very helpful for situations like this.
For instance, Kirkfat could stand on the table on which an object is to be placed, type /locvec and make a note of the Y location and then place the object at that Y location (after calculating the conversion from in-game to Foundry).
When I built the capitol city for Argelius II, it was mostly trial and error - especially since no map available in the Foundry is flat and all building footprints are different (even within the same style).
Glad to hear about the /loc and /locvec commands. That would have been a big help back then - lol. But I'm sure even with those, there is still a lot of fine tuning that will be needed.
Good luck Kirkfat, looking forward to seeing what you come up with (as always )