I think you can always get a most-bins solution by putting as many of the smallest elements in one bin, and then moving on to the next, recursively. (2,2,3), (4,5), (6), (7) is the result for the set you've given.
Jeff japhy Pinyan,
P.L., P.M., P.O.D, X.S.:
Perl,
regex,
and perlhacker How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart