Quote - You can add thickness to an object in Wings, but it's virtually impossible to measure a specific thickness measurement, in proportion to the world scale of the object. 

Not true at all. The default cube in Wings is 2x2x2 wings units. If you treat them as metres you have a 2m cube (or you can type in any specific sizes when you create it). Then if you use any tool it gives you a distance readout to 4 decimal places, so that's accurate to a tenth of a millimetre. Intrude to 0.035 and your cube has walls 35mm thick.