Last weekend I took brother Lurker W. to Willard's BBQ on Willard Rd. near the Expo Center and we discovered something interesting.
I ordered a single-meat platter, for $8.50. Lurker (a well-known New England trencherman) ordered a double-meat platter for $11.50.
Both platters were loaded with food, but the meat piles on both were the exact same size. So for three bucks more you get variety but no more meat. And I suspect the same would apply to the triple-meat platter, which is of course more expensive still.
So unless you really want two different meats, get the single-meat platter. You'll waddle out the same regardless of which you get.