Either way can be done in TMG, it is a matter of preference. I also use one source for a basic source, such as Ohio Deaths 1908 to 1953, and then include the details for the specific individual in the Citation Details.
Please check out the rootsweb list for TMG. The group is fairly active and you will learn of the many ways to tailor TMG for you.
http://lists.rootsweb.ancestry.com/index/other/Software/TMG....