Tdog, I've got one of the Dewalt metal cutting chop saws that uses a carbide balde vs and abrasive wheel. The 14" saw blade had 70 teeth and they don't appear to be anything special. So, for sheet metal, I would try to get a 25-30 teeth carbide blade for the circular saw and try it. Yea the teeth will dull quicker, but on blade shoould be enough to rip all that you would need.
My saw doesn't hardly throw sparkes either.
gary