That's a better idea, a second heat mat*...it's way more efficient, since heat rises (into the cage). I can't tell from your pix, are the hides open at each end? Snakes
prefer only one doorway that's just big enough to get thru (with a meal on board), also a low enough ceiling to afford "back pressure" (a snug feeling). Caves look
very cool to us, but snakes don't feel secure with a wide open end. You can always creatively modify them rather than replace. I know the square black hides aren't
pretty, but snakes do like them; there's other options sold too, depending on availability where you are. Personally, I'd try modifying what you already have.
*If you use a second heat mat, make sure the whole floor is NOT heated...leave an unheated corner for safety, "in case". Snakes do need choices, and sometimes in
shed cycle they prefer lower than normal temperatures too.