There is always a big debate with rose hairs and humidity. The general rule of thumb is substrate dry though. Some people mist there substrate, not the T and have no problems. If she is not climbing the walls or standing on her hide to get away from the damp substrate and you think it will dry out pretty fast then you could probably just leave her on it. Just watch her and use your best judgement. I use the coco fiber substrate myself and it is a BIG pain to dry it out. I just started buying it already dried out in a bag which is a hundred times eaiser. It is probably more cost effect to buy it in a brick and add the water and dry it out yourself but it just takes too long.