I could write down several reasons why being a small fish in a big pond (choosing Duke) is better in this case. However, let me stick to a few big points -
1.) More students in HSM = more employers. I didn't check out Chartis at the time of applying, but there are tons of other payer and provider firms that recruit at Fuqua (especially payer). There are quite a few consulting firms as well. Also, I could write down not one, but several firms which recruit at Fuqua but not at Ross.
2.) HSM has a very solid reputation. Also, better alumni network in the healthcare industry. Think post MBA opportunities.
3.) Concentration of healthcare firms in the RTP area gives you many opportunities to indulge yourself in consulting/internship activities.
4.) There are so many opportunities at Fuqua for the HSM group that it is very difficult to pursue all of them. Check this out, if you haven't already -
current-student-blogs-164691.htmlYou may work at the Duke hospital/medical center, consult CXOs on the hospital's IT/operations strategies and what not.
Having said that, don't bang your head over it right now. I think you have some good options and are looking at things in the right way. Good luck for the rest of the process.
Disclosure - I'm a process consultant in the provider industry and admitted at Duke.