Hey Paul,
That's a good lead. There's a Swenson's not too far from here and they have those "Bird bath bases" Reasonable price too. Funny that I live in a town where there's granite all over the place but I can't get any of it that's useful to me.
Question, what size hole & what are you using for rod? Are you bothering with Stainless? Ot just rebar.
If I use these granite blocks for footings, would that be enough to hold the posts in place, along with the cross bracing without a sill? I'm looking at 8 foot walls, 12 feet total height.
-jeff