large vs small applicator. Is there an advantage to one over the other?

Thank you for your question. Every provider will have their own technique. I would recommend asking for an explanation behind each of two treatment plans and then using that to guide your decision. All the best. Regards, 

The decision on how many applicators to use, where to place them and which size to use in a CoolSculpting treatment is ultimately based on the experience of the physician treating you.  A large applicator versus two small applicators does not necessarily make a difference in the final result, but sometimes two small applicators can be placed differently on one side versus the other or may fit a person's body better than one large applicator.  Using 6 small applicators would cover essentially have the same amount of coverage of 2 large applicators plus 2 small applicators.  It is possible you could get the same result with either method.  

Physicians can have varying recommendations
based upon their own experience with the technology; there is likely no
absolute right or wrong answer here. Generally, as long as the applicators are
attached according to where the bulk of the fat is sitting, and with respect to
the body’s natural curves, similar results could be achieved with either
treatment plan. The surface area a single large applicator will cover is similar
to that of two smalls, though in some cases, utilizing the small applicator
allows for more customized sculpting. Perhaps the only significant difference
between the two recommendations is the amount of time you will spend attached,
as each application will take an hour. If you are still undecided, revisit each
office so they may more thoroughly explain their recommendations, or you may
even seek out an additional physician’s opinion on the matter. Best of luck!