I used UV Mapper Pro 3.5c to make the templates.

If the overlapping pieces are different colors, then they are different material zones and do not affect each other. For example, the central hall ceiling (lower than most, because it is under the main stair landing) is under and overlaps the mezzanine level ceiling template.

But they are different material zones, so what is applied to the central lower hall ceiling will not conflict with what is applied to the mezzanine ceiling.

Similarly, the robin's egg blue areas of the dias map shows flat/horizontal areas (dias floor and step treads). The stair riser template (green and red) overlaps, but they are different material zones; you can draw lines onto the dias map and ignore the stair riser maps. Use the green and red stair riser maps if you want to make your own Alterran text masks, and ignore the dias, bannister, and bannister light templates.

If this method grates on you -everybody has their own way of doing things- I'll soon be able to send "final candidate" OBJ parts if you want to make your own single-material templates. Alternatively, I could try to get UV Mapper Pro 3.5c to output single-material templates, but I don't know if it does that, or how to do so.

This evening got started on a control room piano...

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5