Will the card/paper shrink or buckle when painted/prepared–i.e. is it best to paint before or after construction?
Depends on the model. Interior and hard to reach spots have to be painted beforehand. Some post assembly painting is needed as touch-up anyway. If the sheets have been sprayed with flat acrylic the paper will not get waterlogged and shrink or buckle. (My experience has been that tacky glue still works on paper that has been sprayed with flat clear.