That's very well done! Are you cutting the granite too, or sending it out? If you're cutting it, HOW?
Yes I'm doing the granite fabrication as well. Circular saw outfitted with a diamond blade to section the slabs. Then angle grinder outfitted with a diamond blade to cut close to the circular line. Wood template to grind up to the circle using a z-wheel. Minor adjustments with a metal bond copper pad. Then route the upper and lower edge profile with a diamond profile bit pn my variable speed angle grinder. Just like wood working you can route a profile of your choice including bullnose, ogee etc. Then polish the edges using 9 step resin wet pads.
All of my stoneworking tools are outfitted with a water feed for wet working.
Anchoring to the wood base was done by drilling some holes in the stone, sinking machine screws into the stone, filling the holes with stone epoxy for bonding and then passing the screws through the stretchers and securing with nuts.