Hey there,
the dimensions of the cage look fine, as do the heating/lighting elements, however, I see one/two major flaws. These flaws are the front and the top. I see that there is hardware cloth used as a viewing window on the front, and as a lid to the enclosure. The problem with screening, it allows heat to escape, but more importantly, it allows moisture to escape. I think that moisture is an important aspect of any varanid's husbandry. I make sure all of my animals have adequate humidity levels inside their troughs. Screening does not allow you to control any of these. What I, as well as others use, is acrylic/plexiglass sheeting, that you could buy at the local home depot. Make sure you use a thicker grade, for thinner grades will bend and warp. USe the plexi for a window in the front. As for the top, replace the screening with the plexi. What I do, to allow oxygen/CO2 exchange, is I drill a few holes in the plexiglass top. This does not allow much moisture/humidity to escape, but it does allow some fresh air to circulate.
If you decide to use the screeing, you will have a difficult time getting your substrate to stay moist enough to allow them to burrow. My ackies love to burrow, and they would not be able to if their substrate dried out frequently...
I hope this helps, you can see some pics of my enclosures for my odatria monitors on my site.. try glauerti, tristis, orientalis, acanthurus- I pretty much use the same technique for all of their caging.
Take care, best of luck to you with your soon to be new additions. You'll have a blast with them... Non stop entertainment...
bob
The Odatriad