We use hides in some of the CB70's for the girls who appear to prefer them. There is still a reasonable amout of in hide/out of hide space along with the water bowl.

We had an issue once with the heat tape not being all the way in the groove, probably popped out during shipping. Just reach back there and press down along both edges of it with your finger. Worst case scenario use some aluminum tape if you need to.

With the probe, put it on the outer edges of the heat tape where the tubs angle in towards center. You have about 2 inches to work with there. That way the probe is on the tape but will never be in the way.

Hope this helps, enjoy your racks.