m0useanswered grow question 6mo ago KISS is the accronom that I am filimaer with.
Keep
It
Stupid
Simple
I think your on the right track, I would increase the perlite to around 25-30% though. I find soils compact easily and that can become a problem. I also like to mix in a bit of compost and sometimes Vemiculite but its about the same as perlite.
Slow release fertz are nice, also called amendments, Some of them take forever to break down, others are faster. All depends on the life of the soil, its acidity and the surface area of the product. fine powders have much more surface area then small pebbles of whole things like rocks or shell meals for calcium.
Liwuid for emergences is Key, good plan.