Bottom line is --

Saito / OS / Magnum weight is virtually identical. Buy the one you like and/or trust.

It would be interesting to do a side-by-side run of the saito and OS. Which one pulls the RPM given the exact same prop/fuel/temp, as in swap the prop from one to another, using the same fuel tank and measure with the same tach. I wonder how the Magnum would fair.