thanks for the pics rob or beth or whoever you are.
your setup will ultimately need to be a bit bigger, if i have a proper understanding of the needs of savannah monitors, which i think i do.
also, savs are not desert monitors. it does not look like you keep your sav as such, but it does have some shedding issues.
most fish tank type setups do not properly allow the monitor its humidity needs. savs are not tropical either but need atleast good burrowing abilities to help with their humidity.
i would probably bank a couple bulbs (ie put two 45's or two 60's together side by side over one side of the cage). you will need to bring the basking up to around 130ish. and the overall cage temp would be good at around 84-85ish or around that area, but not 75 as you said.
your sav is bigger too, there is no need now to keep on feeding it insects. fuzzy mice or adult mice will be fine. savs have a tendency to become obese, so 4 a week would be fine for your sav.
my .02,
andrew
-----
Varanus Creations