Today I put some plastic plants in the tubs so the prasinus may feel a bit more secure.
No more heat rock and the basking spot on the higher branches is now reaching 115-120F. That would pretty much cook any snake and Im pretty sure it doesn't get that hot in any rainforest of the world under the sun (perhaps a big rock under the sun but definetely not on a tree branch). But, that is the temperature I found to be ideal by googleing a few caresheets.
I also added a small den to give them opportunity to hide completely if they choose to. They seemed to enjoy it.
New and bigger water bowls were also added. I have seen all 3 monitors drinking from it. The bigger one is sleeping in the water as I type.
Plastic sheets were put over the lids to keep the humidity in. This will be the hardest part because with such a hot basking spot the water must be evaporating pretty quickly.
I still didn't use any substrate to avoid having the crickets hidden and to make it easier detecting the feces.
I didn't see any of them eating in the last couple days, but they all look chunky on their bellies with no skin folds. Right now Im looking at the smaller one and it's tail base is pretty round.
Still below ideal conditions, but the new cages are on their way.
Comments appreciated (especially the critics)
A few pictures now. Here's cage from above, with the basking spot (plastic cover removed):

Both tubs, now there are more secure places:

The cave (still not a suspended one, but I will provide it next week):


This is the smaller monitor, sleeping by the water. He seems to like it. This picture is not so nice but I think it shows his belly looks chunky (I don't really know if prasinus ever get a skin fold if not eating):







