Many of those formulas are variable - the Library of Organic information has a
link with some general information and information about the company web page.
So, a rule of thumb I tend to follow when mixing up something to use as a drench is to add a couple of tablespoons of each ingredient per gallon of water. The place where I stop short is when considering the nature of the products being added. If I'm doing foliar feeding or a drench to fertilize or add biological activity to the soil, I don't add anything that acts like a pesticide or herbicide (such as spinosad or orange oil). I keep it to the Garrett Juice, the bio-stuff, maybe add a dollop of molasses from the kitchen, or even an organic liquid fertilizer. When I plan for killing insect pests I use some orange oil or spinosad and give the garden a bit of a kick by adding Garrett Juice or fertilizer or a sugar, but I don't combine the killing products with the living products. If I'm using Bt (such as Thuricide, for caterpillar control) I don't add orange oil or spinosad, I just add Garrett Juice and maybe some sugar.
I hope that helps.