i would dare you to try something different, and keep your castings lower than your avg organic guy on here.. you can always add more at any time like most guys do.. (we use 15% of total base vs the usual 33% of base, yes less can be more)
Also are these your own castings or store bought?
Reason for all this, better results!
More branches.
Less nodal space.
We rock a peat-free, soon to be dol lime-free mix too, Stow rocks coir grows too, but using peat sometimes i think..
Just do your best first time around, you can always source amendments as you go, and do as many AACT's as you need.. the most important victory is already yours.. you on the organic side.
Most guys go with Sub Cool then tweak but if you want to try something different and achieve surprising results, talk to Don Petro.
He studied everything for months/years, and came up with a good blend that keeps getting more and more simple, yet more and more effective..
We finished finicky 11 wk strains in 1 gal smart pots and had some unreal glossy finishes.. 100 days of just water!! All Ro.. it was really nice way to get into organics!