I think you've picked a winner for your immediate task at hand. I've really never used one of those metal cutting circular saws, but I've heard that they really do a great job. In the past, before I bought the equipment I now have, I've jack-legged around and wasted more time and money trying to make some metal cuts with sawsalls and the thin cutting wheels for grinders. All you'd end up doing there would not only be wasting your time, money and energy, but very possibly wasting some really expensive metal stock. It was a step up when I bought my O/A torch, but last year when I bought my HyperTherm1250 plasma cutter, that's when it flat made it fun for me. I'd bet that it really didn't even take me 30 seconds to make the cuts in the 1/2" table top with that machine. But, it did cost considerably more than your way.
You've gotta let us know how that metal cutting circular saw works. I'm really interested to hear. It looks like it will do the job nicely. Good luck!