benchmark question

I'm going to be testing a NAS solution over NFS. My two main test
benchmark programs will be Iozone and io_profile. The latter is very
new so I'm not expecting anyone to have experience with it (although
if you do the question still applies).

I want to test sequential writes varying from 4k to 150mb from
multiple hosts. I have a compute farm with LSF so getting parallel
processes is not an issue. What are the preferred arguments and
option values for such a test?

IOPS is my primary concern as throughput seems to be less of an issue.

So far my run-through of Iozone looks to take the form:

iozone -RcANw -n 4 -g 150000

Anyone have any comments or suggestions about this?

Thanks.

~F