I'll just answer the humidity question -
if your humidity is already in the 55-70% range, there is nothing additional you need to do to humidify the paper, as long as you are storing your paper in those conditions between printing sessions.
If your paper is too dry, the emulsion will become very slow, you will lose dmax, and you will likely have flocculation in the borders and in continuous tone areas. When printing, if you see significant flocculation in the border areas outside your negative before development, this is a sign that your paper may be too dry. Either that or your lights are running too hot and they are cooking the paper.