How warm of a "basking" area do you think is needed for pregnant female yellow anacondas?

I have a female yellow I jump back and forth with wondering if she is pregnant, but my temps are deffinitely on the cool end and I am very touchy about changing them because of my thermostat configuration and how if affects other snakes.

I played around with the set up a little today and I am debating whether I should change it back and leave her in there, leave it and leave her in there, or remove her and set her up in a better enclosure for pregnancy. I am always hesitant to do a move, or even a big change during pregnancy.

Thoughts?