For Mona, there is really nothing special you need to do. I wouldn't handle her too much though. Just let her rest. As far a getting a weight in her you could put a plate on your scale to create a large base then put her in any bowl or tub on top of the plate. Write down the weight and put her away, then weight just the plate and bowl/tub, subtract from first number = snakes wight.
Can't really tell form the pictures if your other girl in ovulating. But the way she is laying makes me think it could just be building. She will stretch out straight in her tub when she ovulates. She could be at the beginning though. I would check her every few hours.