soil without clay and stone

As you can see in my other posts our soils is built up on fill (it wasn't me.. concrete rubble, asphalt, old bricks). Most of it is tons of woodchips, compost spent potting mix. So I have a LOT of organic matter but no clay and very little sand. I did a jar test and it confirms my suspicion. I think I need to get two things:
1. rock dust (the only thing I came up with so far is crusher dust from the nearest basalt quarry which is not really dust, the particles are mostly bigger)
2. some clay - bentonite?? Something powdered is easy to work with. What other clays are there and is there an advantage of one over the ther?
What do you think? Which type of clay? Application rate? I'm in NSW Australia.
I am reading " the enlivened rock powders" very Steinery and not very practical for me.

With all respect, is it possible you are over-analyzing the problem? Sometimes it's better to charge in with seeds and shovels, win or fail, and learn learn learn from the results.

Personally, I would put roots (seeds) in the ground and let a wide range of annual veggies tell me what they need. My 2c.