baked french toast

I used this recipe a few years ago.
I had made a note to use evaporated milk and sweetened condensed milk as some posters suggested. But I didn't write down the amounts.
The original recipe calls for 2 cups of milk. Do I replace the two cups of milk with 1 cup each of the above?
or 1 cup milk and 1/2 cup each of the above?

Also how many loaves of Challah bread will I need? or If I use Italian or French bread, is it only one layer of bread?

Sorry for all the questions. Thanks!