I turned mine down myself to 1lb 14oz. (at least according to the digital fish scale at the local Portugese liquor store)

The way I decided on this weight was a little more scientific.I cut,and cut, and cut, until I couldn't cut no more! The only way you could get a steel flywheel much lighter would be to cross drill it.
There are some pictures in my images gallery,but beware.If you click on them,they blow up to macro Godzilla size. I'm not so good with computers.