Help Me Choose Timber Nation Rack-- All Wood or Threaded Rod?

I'm using two 1" thick shelves of granite suspended on 4x4 posts tapered at their bottoms.  It's the equivalent of a concrete sofa...and you wouldn't want to stub a toe on it.  Concrete floor.

Vibration isn't an issue here.

Wood, Home Depot, but basically 'scraps'.

The stone  shelves are 'drops' from the countertop/slab shop next door.  Y'all might inquire at a local shop.  You'd be surprised by what they toss.