Hi Reddog, after reading so much info and experiences on this site (aswell as talking to others at bonsai events) I decided to have a go myself last repotting aug/sept. After seeing my PJF suffer with clogged wet soil something needed to be done. I started out just introducing diatomite 50/50 to debco mix (which I'd used obliviously for years), but found I needed more drainage.
Then I was able to trail akadama, so to make the most of it I added it to a mix I based largely on Boon's, yet had to substitute some ingredients due to availability ...
1 part lava rock.
I used hard scoria which I found available graded as 7-10mm at Daico's
1 part pumice.
Couldn't locate a decent size , not included (no bigger than 2mm
) or price in Melbourne
1 part akadama.
Lucky to trial a medium bag
a cup of horticultural charcoal. (easily obtained)
a cup of decomposed granite.
I also found 5-7mm crushed granite (sold as crushed rock/gravel as I recall) at Daico's
Plus 1 part diatomite
I seived and graded all components to get three different sized grades. But also had to wash and dry the scoria and granite to remove the dust.
This mix has perfomered quite well, though a hotter drier summer may have had me a bit more concerned about watering

. Still observing but most are doing better if not thriving
One aspect that has been overlooked in using granite is temperature regulation (IMO)
The best thing with these mixes is that you can store them dry, sealed in containers in the garage and they won't develope mould etc. You don't need top dressing gravel anymore. And when in use, there's no chance of the 'soil' drying out and going aquaphobic.
I am now experimenting with capturing and recycling water runoff
Cheers Ryan