Maybe make it so that the electronic layer has no interactions with the first layer, and doesn't even really exist until u put something in it. This way u wouldnt mess up saves.
Layer 1: Only for pure cosmetics, always sits above normal tpt, no calculations or anything, basicly a transparent drawpad infront of the real tpt.
Layer 2: Real tpt.
Layer 3: Would be connected to layer 2, but cannot be seen unless selected, the only thing moving in here is everything in electronics, and water, but wated wouldn't move, it would just stand still and be conductive.
Almost. "move" is the wrong word =P. As far as interaction between layer 2 and 3, a special element would need to be added that basically sends a spark to the exact same coordinate on the other layer. So if I have this element in layer three at <300,434>, and it gets sparked, then a piece of metal or other conductor at <300,434> on layer two would receive a spark. ---- The ability to see both layers at the same time will need to be an option though. Otherwise, it would be very hard to make something without guessing and checking the placement of components.
Also, I am not sure how copying would work. Would it copy everything on both layers? Just the layer you are on? Or will this be switchable?