Re Shangri-La: I thought the Krung Thep Wing was the older one, the one nearer to the bridge with the balconies and plants on them, a concave arc-shaped building where most rooms face the river. I thought the Shangri-La Wing was the newer one, taller (21 floors of rooms), in the Y shape with one facade facing downriver and one sort of facing upriver (though not with a full-frontal river exposure). In any case, the bottom 13 floors of room in the taller wing are going through extensive renovations at the moment. Not sure if they'll be done by the time the OP will be there.