Thanks. I think maybe my analysis is skewed because of the sieving. The fines that filter through the mesh are maybe like 35% of the total matter.
Do you think there may be wisdom in drying a new sample, then grinding the materials and finally sieving the ground matter for analysis?
Alternatively would adding in rice hulls, scoria or something like perlite be useful?
Screening the sample was correct.
It is clear from your soil description and the time it takes to dry out, that your mix is too heavy. It needs to dry out every day, all by itself.
This will allow for maximum calcium uptake, which is the most difficult thing to achieve.
Rice hulls are good, perlite in big pieces, no fines. Scroria that is inert would be great. Big peat, no fines also works well. Small pieces of decomposed wood, but this amendment will require a bit more N during your cycle, but the good biology food source is priceless.