Looking forward to your updates Tim!
Aeration, as you are probably aware is a big part of landscapers efforts to rejuvenate lawns, your efforts to open up the soil remind me of those fertilizer machines which plug little holes in the ground as they spread the nutrients.
The bonsai folks insist on using only large particle ingredients in their soils to keep the pores open and allow air transfer during watering. I read in a bonsai book that the air/soil around the roots becomes toxic as the roots digest nutrients, a porous soil allows for the area around the roots to be cleansed during watering, this could be important for semps to as they are also a slow growing plants (compared to things like vegetables and weeds). I've certainly found that they prefer open soil, the dense mud we have around here is no good for growing them, I tried growing my first "fancy" NoIDs in the native soil for three years before I picked up a book on hardy succulents to try and figure out why they weren't growing, when I dug them up to atone for my sin of using dense clay, the roots were in shockingly poor shape, stunted, gnarled and some were even being preyed upon by subterranean pests taking advantage of their weakened state. Never again will I subject sempervivum to such a tortured existence. Good fluffy soil is key. Very much hoping you're experiment pans out.
-Sol
