Re: prop diameter change
Like Dhadley said, it all depends on the prop design. You'll see more change from switching materials (Al to SS) and from switching brands (design) than from that insignificant change in diameter. If it fits on the prop shaft, you'll have no compatibilty issues etc.
Do you know what was the rpm of the engine with the old prop? Speed? Assuming your old prop was also a general purpose prop, you might get a bit more speed out of the new prop because its SS, and may lose a bit of hole shot, but you won't really know until you try it out.
If the price is good, get it and let us know what happens. We'll all become wiser.