If you have transplanted a reveg candidate into a larger container at the beginning of the process, you are in a low light situation, and roots are not actively growing into the fresh medium, how does the fresh medium dry out?
Unless you're talking about general evaporation, which will take much longer than the 'core' that you transplanted, to dry out.. if you wait for that fresh, un-rooted, medium to dry out, your core is going to be too dry..
Yes, it is doable, with an experienced eye.. but for someone who is new to reveg, probably easier, and a higher chance for success, by just leaving the plant in its original container until it shows new veg growth..
Also, you save the medium if the reveg doesn't work, and the plant pukes out..