Hi Rufus,
That's a nice machine and a nice bench.
I picked up the same machine and I'm stuck in sort of an "analysis paralysis" on the bench construction. The machine came with a 30" x 72" steel top workbench, but no support to speak of below the steel top. The manual recommends a heavy flat bar mounting, with jack screws to adjust the bed. I'm toying with the idea of some angle iron below the steel surface, but also wondering if some plain old 2x6s would be enough.
Can you share how yours is supported, and how it's working out for you?
Thanks,
TomKro