I'm not attacking you, but I'm really trying to get my point across here, I hope you get it, and understand.
Please, listen carefully...
let the monitor tell YOU what it will and won't eat, and how much. YOU don't decide ANYthing, ok? The reason being, you are not a monitor.
Rather than think you know better than it, what it needs, let it tell you. And it will. 
If it is still eating crickets, by all means, let it eat them. In nature, even large monitors, will still eat bugs.
You can offer the rodents, and if it eats them, good, if it doesn't, good then too. Do not give a flying %$^& what other people's monitors eat, let yours tell you what it needs.
Yours may stop eating crickets, fine, you can still offer them .
Yours may not eat the rodents, fine, you can still try once in a while. It will most likely eventually eat them.
As for eating one a day,..??? You don't know if that is enough or not, and neither does anybody on the net. We are all just people. But your monitor knows.
He will let you know. Go by how hungry he acts. If he attacks the food, offer more. If he has to be coaxed to eat it, he is not hungry (or shy). Try again the next day or so.
The answer is in your animal, not a computer screen.
D.