optimizing load balance

I've been using pmetis in the trivial (to metis) case of
node weights and no edges. i.e the first few lines in my
weight file are:
1155 0 10
369.461
388.384
312.23
with a max value of 519.692 and a min value of 7.15386
(the numbers are my proxy measure for neuron complexity
(499 cells broken into 1155 pieces) and I need to
place the pieces onto 1024 cpus in a balanced fashion).

Anyway, pmetis yields
**********************************************************************
METIS 4.0.1 Copyright 1998, Regents of the University of Minnesota

Graph Information ---------------------------------------------------
Name: balbb520.wt.dat, #Vertices: 1155, #Edges: 0, #Parts: 1024

Recursive Partitioning... -------------------------------------------
1024-way Edge-Cut: 0, Balance: 1.55

Timing Information --------------------------------------------------
I/O: 0.000
Partitioning: 0.010 (PMETIS time)
Total: 0.010
**********************************************************************

whereas a naive greedy method (sort the weights
and fill each cpu in turn using the maximum unused
weights that do not sum greater than some threshold)
gives a balance of 1.17. So I am wondering if I am
misusing METIS and if there is a way to cast the problem
to reliably get nearly optimum load balance.