Changing from sub-folder to sub-domain

I have a network with only 3 sites and 2 have been domain mapped. I know believe I need to switch this network to subdomain install instead.

I've read that I can change the setup in wp-config.php but I want confirmation first that this is doable and will continue to work with Prosites, Domain Mapping, and ultimately Multi Domain.

Has anyone done this? Any thoughts to share about the sub-domain vs. sub-directory installs are welcome and appreciated!