Congrats on your future new addition!

Some suggestions:

I would bump up your warm side temps to ~89-92, that's what my ranges are for my BPs.

Your cold side should be okay, sometimes my tubs get as low as 75 degrees ambient (from the cooler winter temps) and everyone is healthy and fine as long as they have the appropriate warm side temps.

I would get two identical hides for the warm and cold side.

I would get some tank lid clips for the lid instead of using books. Much more sturdy. Also cover most of the lid with tin foil to keep in temps and humidity since your bulb will suck all humidity.

I would feed in the tank and 10-15% of your snake's body weight. Pick up a digital scale from Walmart or similar stores.

How are you measuring temps?